tips fro sql

8/12/2019 Tips Fro SQL

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Training from W3Schools

Introduction to SQL

SQL is a standard language for accessing and manipulating databases.

What is SQL?

SQL stands for Structured Query Language

SQL lets you access and manipulate databases

SQL is an ANSI (American National Standards Institute) standard

What Can SQL do?

SQL can execute queries against a database

SQL can retrieve data from a database

SQL can insert records in a database

SQL can update records in a database

SQL can delete records from a database

SQL can create ne databases

SQL can create ne tables in a database

SQL can create stored procedures in a database

SQL can create vies in a database

SQL can set permissions on tables! procedures! and vies

SQL is a Standard - BUT....

Alt"oug" SQL is an ANSI (American National Standards Institute) standard! t"ere are manydifferent versions of t"e SQL language.


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#oever! to be compliant it" t"e ANSI standard! t"ey all support at least t"e ma$or commands

(suc" as S%L%&'! *A'%! *%L%'%! INS%+'! ,#%+%) in a similar manner.

Note:-ost of t"e SQL database programs also "ave t"eir on proprietary extensions in additionto t"e SQL standard

Using SQL in Your Web Site

'o build a eb site t"at s"os some data from a database! you ill need t"e folloing/

An +*0-S database program (i.e. -S Access! SQL Server! -ySQL)

A server1side scripting language! li2e # or AS

SQL

#'-L 3 &SS

RDBMS

+*0-S stands for +elational *atabase -anagement System.

+*0-S is t"e basis for SQL! and for all modern database systems li2e -S SQL Server! I0-

*04! 5racle! -ySQL! and -icrosoft Access.

'"e data in +*0-S is stored in database ob$ects called tables.

A table is a collections of related data entries and it consists of columns and ros.

Database Tabes

A database most often contains one or more tables. %ac" table is identified by a name (e.g.

6&ustomers6 or 65rders6). 'ables contain records (ros) it" data.

0elo is an example of a table called 6ersons6/

!"#d LastNa$e %irstNa$e &ddress Cit'

7 #ansen 5la 'imoteivn 78 Sandnes

4 Svendson 'ove 0orgvn 49 Sandnes

9 ettersen :ari Storgt 48 Stavanger


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'"e table above contains t"ree records (one for eac" person) and five columns (;Id! LastName!


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'"e **L part of SQL permits database tables to be created or deleted. It also define indexes

(2eys)! specify lin2s beteen tables! and impose constraints beteen tables. '"e most important

**L statements in SQL are/

CR,&T, D&T&B&S,1 creates a ne database

&LT,R D&T&B&S,1 modifies a database

CR,&T, T&BL,1 creates a ne table

&LT,R T&BL,1 modifies a table

DR! T&BL,1 deletes a table

CR,&T, #ND,1 creates an index (searc" 2ey)

DR! #ND,1 deletes an index

SQL SELECT Statement

'"is c"apter ill explain t"e S%L%&' and t"e S%L%&' = statements.

The SQL S,L,CT State$ent

'"e S%L%&' statement is used to select data from a database.

'"e result is stored in a result table! called t"e result1set.

SQL SELECT Syntax

SELECT column_name(s)

FROM table_name

and

SELECT * FROM table_name

Note:SQL is not case sensitive. S%L%&' is t"e same as select.

&n SQL S,L,CT ,/a$)e

'"e 6ersons6 table/


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P_Id LastName FirstName Address City

1 Hansen Ola Timoteivn 10 Sandnes

Svendson Tove !o"#vn $ Sandnes

$ %ette"sen &a"i Sto"#t 0 Stavan#e"

No e ant to select t"e content of t"e columns named 6LastName6 and 6


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SQL SELECT DISTINCT Statement

'"is c"apter ill explain t"e S%L%&' *IS'IN&' statement.

The SQL S,L,CT D#ST#NCT State$ent

In a table! some of t"e columns may contain duplicate values. '"is is not a problem! "oever!

sometimes you ill ant to list only t"e different (distinct) values in a table.

'"e *IS'IN&' 2eyord can be used to return only distinct (different) values.

SQL SELECT DISTINCT Syntax

SELECT ST'CT column_name(s)

FROM table_name

S,L,CT D#ST#NCT ,/a$)e

'"e 6ersons6 table/





No e ant to select only t"e distinct values from t"e column named 6&ity6 from t"e tableabove.

,e use t"e folloing S%L%&' statement/


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SELECT ST'CT Cit+ FROM %e"sons

'"e result1set ill loo2 li2e t"is/

City

Sandnes

Stavan#e"

SQL WHEE Clause

'"e ,#%+% clause is used to filter records.

The W1,R, Cause

'"e ,#%+% clause is used to extract only t"ose records t"at fulfill a specified criterion.

SQL WHEE Syntax


FROM table_name,HERE column_name o-e"ato" value

W1,R, Cause ,/a$)e

'"e 6ersons6 table/






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No e ant to select only t"e persons living in t"e city 6Sandnes6 from t"e table above.


SELECT * FROM %e"sons

,HERE Cit+./Sandnes/





Quotes &round Te/t %ieds

SQL uses single quotes around text values (most database systems ill also accept doublequotes).

Alt"oug"! numeric values s"ould not be enclosed in quotes.


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SELECT * FROM %e"sons ,HERE 3ea"./1456/

)erators &o2ed in the W1,R, Cause,it" t"e ,#%+% clause! t"e folloing operators can be used/

Operator Description

. E7ual

89 'ot e7ual

9 :"eate" tan

8 Less tan

9. :"eate" tan o" e7ual

8. Less tan o" e7ual

!ET,EE

'!et2een an inclusive "an#e

L&E Sea"c ;o" a -atte"n

' ; +ou ? operator may be ritten as @

SQL !ND " # #$erators

'"e AN* 5+ operators are used to filter records based on more t"an one condition.

The &ND 3 R )erators

'"e AN* operator displays a record if bot" t"e first condition and t"e second condition is true.


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'"e 5+ operator displays a record if eit"er t"e first condition or t"e second condition is true.

&ND )erator ,/a$)e

'"e 6ersons6 table/





No e ant to select only t"e persons it" t"e first name equal to 6'ove6 AN* t"e last name

equal to 6Svendson6/



,HERE Fi"st'ame./Tove/

>' Last'ame./Svendson/




R )erator ,/a$)e

No e ant to select only t"e persons it" t"e first name equal to 6'ove6 5+ t"e first name

equal to 65la6/



,HERE Fi"st'ame./Tove/

OR Fi"st'ame./Ola/


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Co$bining &ND 3 R

Bou can also combine AN* and 5+ (use parent"esis to form complex expressions).

No e ant to select only t"e persons it" t"e last name equal to 6Svendson6 AN* t"e firstname equal to 6'ove6 5+ to 65la6/


SELECT * FROM %e"sons ,HERE

Last'ame./Svendson/

>' (Fi"st'ame./Tove/ OR Fi"st'ame./Ola/)




SQL #DE %& 'ey(ord

'"e 5+*%+ 0B 2eyord is used to sort t"e result1set.

The RD,R BY (e'2ord

'"e 5+*%+ 0B 2eyord is used to sort t"e result1set by a specified column.

'"e 5+*%+ 0B 2eyord sort t"e records in ascending order by default.

If you ant to sort t"e records in a descending order! you can use t"e *%S& 2eyord.


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SQL #DE %& Syntax


FROM table_name

ORER !3 column_name(s) >SC?ESC

RD,R BY ,/a$)e

'"e 6ersons6 table/





@ 'ilsen Tom Ain#vn $ Stavan#e"

No e ant to select all t"e persons from t"e table above! "oever! e ant to sort t"e persons

by t"eir last name.


SELECT * FROM %e"sons ORER !3 Last'ame







RD,R BY D,SC ,/a$)e


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No e ant to select all t"e persons from t"e table above! "oever! e ant to sort t"e persons

descending by t"eir last name.


SELECT * FROM %e"sonsORER !3 Last'ame ESC







SQL INSET INT# Statement

'"e INS%+' IN'5 statement is used to insert ne records in a table.

The #NS,RT #NT State$ent

'"e INS%+' IN'5 statement is used to insert a ne ro in a table.

SQL INSET INT# Syntax

It is possible to rite t"e INS%+' IN'5 statement in to forms.

'"e first form doesnCt specify t"e column names "ere t"e data ill be inserted! only t"eir

values/

'SERT 'TO table_name

A>LBES (value1 value value$)


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'"e second form specifies bot" t"e column names and t"e values to be inserted/

'SERT 'TO table_name (column1 column column$)


SQL #NS,RT #NT ,/a$)e

,e "ave t"e folloing 6ersons6 table/





No e ant to insert a ne ro in t"e 6ersons6 table.

,e use t"e folloing SQL statement/

'SERT 'TO %e"sons

A>LBES (@/'ilsen/ /Doan/ /!a


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'"e folloing SQL statement ill add a ne ro! but only add data in t"e 6;Id6! 6LastName6

and t"e 6


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SQL U!D&T, ,/a$)e

'"e 6ersons6 table/





@ 'ilsen Doan !a


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B%>TE %e"sons

SET >dd"ess./'issestien 5/ Cit+./Sandnes/

'"e 6ersons6 table ould "ave loo2ed li2e t"is/


1 Hansen Ola 'issestien 5 Sandnes

Svendson Tove 'issestien 5 Sandnes

$ %ette"sen &a"i 'issestien 5 Sandnes

@ 'ilsen Doan 'issestien 5 Sandnes

6 Tessem Da


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Note:0e very careful "en deleting records. Bou cannot undo t"is statement

SQL T#* Clause

The T! Cause

'"e '5 clause is used to specify t"e number of records to return.

'"e '5 clause can be very useful on large tables it" t"ousands of records. +eturning a largenumber of records can impact on performance.

Note:Not all database systems support t"e '5 clause.

SQL Ser+er SyntaxSELECT TO% numbe"?-e"cent column_name(s)

FROM table_name

SQL S,L,CT T! ,4ui5aent in M'SQL and ra*e

,ySQL Syntax


FROM table_name

LMT numbe"

Exam$le

SELECT *

FROM %e"sons

LMT 6

#racle Syntax


FROM table_name,HERE RO,'BM 8. numbe"

Exam$le

SELECT *

FROM %e"sons ,HERE RO,'BM 8.6


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SQL T! ,/a$)e

'"e 6ersons6 table/






No e ant to select only t"e to first records in t"e table above.


SELECT TO% * FROM %e"sons





SQL T! !,RC,NT ,/a$)e

'"e 6ersons6 table/





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No e ant to select only E8F of t"e records in t"e table above.


SELECT TO% 60 %ERCE'T * FROM %e"sons





SQL LI'E #$erator

'"e LI:% operator is used in a ,#%+% clause to searc" for a specified pattern in a column.

The L#(, )erator

'"e LI:% operator is used to searc" for a specified pattern in a column.

SQL LI'E Syntax


FROM table_name

,HERE column_name L&E -atte"n

L#(, )erator ,/a$)e

'"e 6ersons6 table/


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No e ant to select t"e persons living in a city t"at starts it" 6s6 from t"e table above.



,HERE Cit+ L&E /sG/

'"e 6F6 sign can be used to define ildcards (missing letters in t"e pattern) bot" before andafter t"e pattern.






Next! e ant to select t"e persons living in a city t"at ends it" an 6s6 from t"e 6ersons6 table.



,HERE Cit+ L&E /Gs/






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Next! e ant to select t"e persons living in a city t"at contains t"e pattern 6tav6 from t"e

6ersons6 table.


SELECT * FROM %e"sons,HERE Cit+ L&E /GtavG/




It is also possible to select t"e persons living in a city t"at N5' contains t"e pattern 6tav6 from

t"e 6ersons6 table! by using t"e N5' 2eyord.



,HERE Cit+ 'OT L&E /GtavG/





SQL Wildcards

SQL ildcards can be used "en searc"ing for data in a database.

SQL Wid*ards

SQL ildcards can substitute for one or more c"aracters "en searc"ing for data in a database.


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SQL ildcards must be used it" t"e SQL LI:% operator.

,it" SQL! t"e folloing ildcards can be used/

Wildcard Description

G > substitute ;o" e"o o" mo"e ca"acte"s

_ > substitute ;o" e=actl+ one ca"acte"

Ica"listJ >n+ sin#le ca"acte" in ca"list

IKca"listJ

or

Gc"arlistH

>n+ sin#le ca"acte" not in ca"list

SQL Wid*ard ,/a$)es






Using the 6 Wid*ard

No e ant to select t"e persons living in a city t"at starts it" 6sa6 from t"e 6ersons6 table.



,HERE Cit+ L&E /saG/



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Next! e ant to select t"e persons living in a city t"at contains t"e pattern 6nes6 from t"e

6ersons6 table.



,HERE Cit+ L&E /GnesG/





Using the " Wid*ardNo e ant to select t"e persons it" a first name t"at starts it" any c"aracter! folloed by6la6 from t"e 6ersons6 table.



,HERE Fi"st'ame L&E /_la/





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Next! e ant to select t"e persons it" a last name t"at starts it" 6S6! folloed by any

c"aracter! folloed by 6end6! folloed by any c"aracter! folloed by 6on6 from t"e 6ersons6

table.



,HERE Last'ame L&E /S_end_on/




Using the 7*harist8 Wid*ard

No e ant to select t"e persons it" a last name t"at starts it" 6b6 or 6s6 or 6p6 from t"e

6ersons6 table.



,HERE Last'ame L&E /Ibs-JG/





Next! e ant to select t"e persons it" a last name t"at do not start it" 6b6 or 6s6 or 6p6 from

t"e 6ersons6 table.



,HERE Last'ame L&E /Ibs-JG/


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SQL IN #$erator

The #N )erator

'"e IN operator allos you to specify multiple values in a ,#%+% clause.

SQL IN Syntax


FROM table_name

,HERE column_name ' (value1value)

#N )erator ,/a$)e

'"e 6ersons6 table/





No e ant to select t"e persons it" a last name equal to 6#ansen6 or 6ettersen6 from t"etable above.



,HERE Last'ame ' (/Hansen//%ette"sen/)


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SQL %ETWEEN #$erator

'"e 0%',%%N operator is used in a ,#%+% clause to select a range of data beteen to

values.

The B,TW,,N )erator

'"e 0%',%%N operator selects a range of data beteen to values. '"e values can be

numbers! text! or dates.

SQL %ETWEEN Syntax


FROM table_name

,HERE column_name

!ET,EE' value1 >' value

B,TW,,N )erator ,/a$)e

'"e 6ersons6 table/






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No e ant to select t"e persons it" a last name alp"abetically beteen 6#ansen6 and

6ettersen6 from t"e table above.


SELECT * FROM %e"sons,HERE Last'ame

!ET,EE' /Hansen/ >' /%ette"sen/




Note:'"e 0%',%%N operator is treated differently in different databases.

In some databases! persons it" t"e LastName of 6#ansen6 or 6ettersen6 ill not be listed!

because t"e 0%',%%N operator only selects fields t"at are beteen and excluding t"e testvalues).

In ot"er databases! persons it" t"e LastName of 6#ansen6 or 6ettersen6 ill be listed! because

t"e 0%',%%N operator selects fields t"at are beteen and including t"e test values).

And in ot"er databases! persons it" t"e LastName of 6#ansen6 ill be listed! but 6ettersen6ill not be listed (li2e t"e example above)! because t"e 0%',%%N operator selects fields

beteen t"e test values! including t"e first test value and excluding t"e last test value.

'"erefore/ &"ec2 "o your database treats t"e 0%',%%N operator.

,/a$)e 9

'o display t"e persons outside t"e range in t"e previous example! use N5' 0%',%%N/


,HERE Last'ame'OT !ET,EE' /Hansen/ >' /%ette"sen/




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SQL !lias

,it" SQL! an alias name can be given to a table or to a column.

SQL &ias

Bou can give a table or a column anot"er name by using an alias. '"is can be a good t"ing to doif you "ave very long or complex table names or column names.

An alias name could be anyt"ing! but usually it is s"ort.

SQL !lias Syntax for Ta-les


FROM table_name

>S alias_name

SQL !lias Syntax for ColumnsSELECT column_name >S alias_name

FROM table_name

&ias ,/a$)e

Assume e "ave a table called 6ersons6 and anot"er table called 6roduct;5rders6. ,e ill

give t"e table aliases of 6p6 and 6po6 respectively.

No e ant to list all t"e orders t"at 65la #ansen6 is responsible for.


SELECT -oO"de" -Last'ame -Fi"st'ame

FROM %e"sons >S -


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%"oduct_O"de"s >S -o

,HERE -Last'ame./Hansen/ >' -Fi"st'ame./Ola/

'"e same S%L%&' statement it"out aliases/

SELECT %"oduct_O"de"sO"de" %e"sonsLast'ame %e"sonsFi"st'ame

FROM %e"sons

%"oduct_O"de"s

,HERE %e"sonsLast'ame./Hansen/ >' %e"sonsFi"st'ame./Ola/

As youCll see from t"e to S%L%&' statements above aliases can ma2e queries easier to bot"rite and to read.

SQL .oins

SQL $oins are used to query data from to or more tables! based on a relations"ip beteen

certain columns in t"ese tables.

SQL #N

'"e D5IN 2eyord is used in an SQL statement to query data from to or more tables! based on

a relations"ip beteen certain columns in t"ese tables.

'ables in a database are often related to eac" ot"er it" 2eys.

A primary 2ey is a column (or a combination of columns) it" a unique value for eac" ro.

%ac" primary 2ey value must be unique it"in t"e table. '"e purpose is to bind data toget"er!

across tables! it"out repeating all of t"e data in every table.

Loo2 at t"e 6ersons6 table/






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Note t"at t"e 6;Id6 column is t"e primary 2ey in t"e 6ersons6 table. '"is means t"at noto

ros can "ave t"e same ;Id. '"e ;Id distinguis"es to persons even if t"ey "ave t"e same

name.

Next! e "ave t"e 65rders6 table/

O_Id OrderNo P_Id

1 46 $

@@5 $

$ @65 1

@ @65 1

6 $@5@ 16

Note t"at t"e 65;Id6 column is t"e primary 2ey in t"e 65rders6 table and t"at t"e 6;Id6 column

refers to t"e persons in t"e 6ersons6 table it"out using t"eir names.

Notice t"at t"e relations"ip beteen t"e to tables above is t"e 6;Id6 column.

Di++erent SQL #Ns

0efore e continue it" examples! e ill list t"e types of D5IN you can use! and t"edifferences beteen t"em.

JOIN Retu"n "o2s 2en te"e is at least one matc in bot tables

LEFT JOIN Retu"n all "o2s ;"om te le;t table even i; te"e a"e no matces in te "i#t

table

RIGT JOIN Retu"n all "o2s ;"om te "i#t table even i; te"e a"e no matces in te le;t

table

F!LL JOIN Retu"n "o2s 2en te"e is a matc in one o; te tables

SQL INNE .#IN 'ey(ord

SQL #NN,R #N (e'2ord

'"e INN%+ D5IN 2eyord return ros "en t"ere is at least one matc" in bot" tables.


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SQL INNE .#IN Syntax


FROM table_name1

''ER DO' table_name

O' table_name1column_name.table_namecolumn_name

!S:INN%+ D5IN is t"e same as D5IN.

SQL #NN,R #N ,/a$)e

'"e 6ersons6 table/





'"e 65rders6 table/

O_Id OrderNo P_Id

1 46 $

@@5 $

$ @65 1

@ @65 1

6 $@5@ 16

No e ant to list all t"e persons it" any orders.


SELECT %e"sonsLast'ame %e"sonsFi"st'ame O"de"sO"de"'o

FROM %e"sons

''ER DO' O"de"s

O' %e"sons%_d.O"de"s%_d


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ORER !3 %e"sonsLast'ame


LastName FirstName OrderNo

Hansen Ola @65

Hansen Ola @65

%ette"sen &a"i 46

%ette"sen &a"i @@5

'"e INN%+ D5IN 2eyord return ros "en t"ere is at least one matc" in bot" tables. If t"ere

are ros in 6ersons6 t"at do not "ave matc"es in 65rders6! t"ose ros ill N5' be listed.

SQL LE/T .#IN 'ey(ord

SQL L,%T #N (e'2ord

'"e L%


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'"e 65rders6 table/

O_Id OrderNo P_Id

1 46 $

@@5 $

$ @65 1

@ @65 1

6 $@5@ 16

No e ant to list all t"e persons and t"eir orders 1 if any! from t"e tables above.



FROM %e"sons

LEFT DO' O"de"sO' %e"sons%_d.O"de"s%_d




Hansen Ola @65

Hansen Ola @65

%ette"sen &a"i 46

%ette"sen &a"i @@5

Svendson Tove


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'"e L%


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@ @65 1

6 $@5@ 16

No e ant to list all t"e orders it" containing persons 1 if any! from t"e tables above.



FROM %e"sons

R:HT DO' O"de"s





Hansen Ola @65

Hansen Ola @65

%ette"sen &a"i 46

%ette"sen &a"i @@5

$@5@

'"e +IJ#' D5IN 2eyord returns all t"e ros from t"e rig"t table (5rders)! even if t"ere are no

matc"es in t"e left table (ersons).

SQL /)LL .#IN 'ey(ord

SQL %ULL #N (e'2ord'"e


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FBLL DO' table_name


SQL %ULL #N ,/a$)e

'"e 6ersons6 table/





'"e 65rders6 table/

O_Id OrderNo P_Id

1 46 $

@@5 $

$ @65 1

@ @65 1

6 $@5@ 16

No e ant to list all t"e persons and t"eir orders! and all t"e orders it" t"eir persons.



FROM %e"sonsFBLL DO' O"de"s





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Hansen Ola @65

Hansen Ola @65

%ette"sen &a"i 46

%ette"sen &a"i @@5

Svendson Tove

$@5@

'"e


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SQL )NI#N !LL Syntax

SELECT column_name(s) FROM table_name1

B'O' >LL

SELECT column_name(s) FROM table_name

!S:'"e column names in t"e result1set of a NI5N are alays equal to t"e column names in t"e

first S%L%&' statement in t"e NI5N.

SQL UN#N ,/a$)e

Loo2 at t"e folloing tables/


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SELECT E_'ame FROM Em-lo+ees_BS>


E_Name

Hansen Ola

Svendson Tove

Svendson Ste-en

%ette"sen &a"i

Tu"ne" Sall+

&ent Cla"LL

SELECT E_'ame FROM Em-lo+ees_BS>

Resut

E_Name

Hansen Ola

Svendson Tove

Svendson Ste-en

%ette"sen &a"i


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Tu"ne" Sall+

&ent Cla"R3 &E3

FORE:' &E3

CHEC&

EF>BLT

'"e next c"apters ill describe eac" constraint in details.

SQL N#T N)LL Constraint

0y default! a table column can "old NLL values.

SQL NT NULL Constraint'"e N5' NLL constraint enforces a column to N5' accept NLL values.

'"e N5' NLL constraint enforces a field to alays contain a value. '"is means t"at you

cannot insert a ne record! or update a record it"out adding a value to t"is field.

'"e folloing SQL enforces t"e 6;Id6 column and t"e 6LastName6 column to not accept

NLL values/

CRE>TE T>!LE %e"sons

(%_d int 'OT 'BLL

Last'ame va"ca"(66) 'OT 'BLL

Fi"st'ame va"ca"(66)

>dd"ess va"ca"(66)

Cit+ va"ca"(66)

)


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SQL )NIQ)E Constraint

SQL UN#QU, Constraint'"e NIQ% constraint uniquely identifies eac" record in a database table.

'"e NIQ% and +I-A+B :%B constraints bot" provide a guarantee for uniqueness for a

column or set of columns.

A +I-A+B :%B constraint automatically "as a NIQ% constraint defined on it.

Note t"at you can "ave many NIQ% constraints per table! but only one +I-A+B :%B

constraint per table.

SQL UN#QU, Constraint on CR,&T, T&BL,

'"e folloing SQL creates a NIQ% constraint on t"e 6;Id6 column "en t"e 6ersons6table is created/

M'SQL:


(

%_d int 'OT 'BLL



>dd"ess va"ca"(66)

Cit+ va"ca"(66)

B'NBE (%_d)

)

SQL Ser5er > ra*e > MS &**ess:


(

%_d int 'OT 'BLL B'NBE



>dd"ess va"ca"(66)

Cit+ va"ca"(66)


48/107

)

'o allo naming of a NIQ% constraint! and for defining a NIQ% constraint on multiplecolumns! use t"e folloing SQL syntax/

M'SQL > SQL Ser5er > ra*e > MS &**ess:


(

%_d int 'OT 'BLL



>dd"ess va"ca"(66)

Cit+ va"ca"(66)

CO'STR>'T uc_%e"son B'NBE (%_dLast'ame)

)

SQL UN#QU, Constraint on &LT,R T&BL,

'o create a NIQ% constraint on t"e 6;Id6 column "en t"e table is already created! use t"e

folloing SQL/


>LTER T>!LE %e"sons

> B'NBE (%_d)

'o allo naming of a NIQ% constraint! and for defining a NIQ% constraint on multiplecolumns! use t"e folloing SQL syntax/


>LTER T>!LE %e"sons

> CO'STR>'T uc_%e"son B'NBE (%_dLast'ame)

To DR! a UN#QU, Constraint

'o drop a NIQ% constraint! use t"e folloing SQL/


49/107

M'SQL:

>LTER T>!LE %e"sons

RO% 'E uc_%e"son


>LTER T>!LE %e"sons

RO% CO'STR>'T uc_%e"son

SQL *I,!& 'E& Constraint

SQL !R#M&RY (,Y Constraint

'"e +I-A+B :%B constraint uniquely identifies eac" record in a database table.

rimary 2eys must contain unique values.

A primary 2ey column cannot contain NLL values.

%ac" table s"ould "ave a primary 2ey! and eac" table can "ave only 5N% primary 2ey.

SQL !R#M&RY (,Y Constraint on CR,&T, T&BL,

'"e folloing SQL creates a +I-A+B :%B on t"e 6;Id6 column "en t"e 6ersons6 table is

created/

M'SQL:


(

%_d int 'OT 'BLL

Last'ame va"ca"(66) 'OT 'BLLFi"st'ame va"ca"(66)

>dd"ess va"ca"(66)

Cit+ va"ca"(66)

%RM>R3 &E3 (%_d)

)


50/107



(

%_d int 'OT 'BLL %RM>R3 &E3

Last'ame va"ca"(66) 'OT 'BLLFi"st'ame va"ca"(66)

>dd"ess va"ca"(66)

Cit+ va"ca"(66)

)

'o allo naming of a +I-A+B :%B constraint! and for defining a +I-A+B :%B constraint

on multiple columns! use t"e folloing SQL syntax/



(

%_d int 'OT 'BLL



>dd"ess va"ca"(66)

Cit+ va"ca"(66)

CO'STR>'T - %RM>R3 &E3 (%_d)

'o allo naming of a +I-A+B :%B constraint! and for defining a +I-A+B :%B constrainton multiple columns! use t"e folloing SQL syntax/



51/107

>LTER T>!LE %e"sons

> CO'STR>'T -LTER T>!LE %e"sons

RO% %RM>R3 &E3


>LTER T>!LE %e"sons

RO% CO'STR>'T -


52/107

O_Id OrderNo P_Id

1 46 $

@@5 $

$ @65

@ @65 1

Note t"at t"e 6;Id6 column in t"e 65rders6 table points to t"e 6;Id6 column in t"e 6ersons6

table.

'"e 6;Id6 column in t"e 6ersons6 table is t"e +I-A+B :%B in t"e 6ersons6 table.

'"e 6;Id6 column in t"e 65rders6 table is a ra*e > MS &**ess:

CRE>TE T>!LE O"de"s

(


53/107

O_d int 'OT 'BLL %RM>R3 &E3

O"de"'o int 'OT 'BLL

%_d int FORE:' &E3 REFERE'CES %e"sons(%_d)

)

'o allo naming of a SQL Ser5er > ra*e > MS &**ess:

>LTER T>!LE O"de"s

> CO'STR>'T ;


54/107

To DR! a %R,#;N (,Y Constraint

'o drop a ra*e > MS &**ess:

>LTER T>!LE O"de"s

RO% CO'STR>'T ;


55/107



>dd"ess va"ca"(66)

Cit+ va"ca"(66)

CHEC& (%_d90)

)



(

%_d int 'OT 'BLL CHEC& (%_d90)



>dd"ess va"ca"(66)

Cit+ va"ca"(66))

'o allo naming of a %&: constraint! and for defining a %&: constraint on multiple

columns! use t"e folloing SQL syntax/



(

%_d int 'OT 'BLL



>dd"ess va"ca"(66)

Cit+ va"ca"(66)

CO'STR>'T c


56/107

> CHEC& (%_d90)

'o allo naming of a %&: constraint! and for defining a %&: constraint on multiplecolumns! use t"e folloing SQL syntax/


>LTER T>!LE %e"sons

> CO'STR>'T c ra*e > MS &**ess:

>LTER T>!LE %e"sons

RO% CO'STR>'T c


57/107



>dd"ess va"ca"(66)

Cit+ va"ca"(66) EF>BLT /Sandnes/

)

'"e *%BLT :ET>TE()

)

SQL D,%&ULT Constraint on &LT,R T&BL,

'o create a *%LTER T>!LE %e"sons

>LTER Cit+ SET EF>BLT /S>''ES/


>LTER T>!LE %e"sons

>LTER COLBM' Cit+ SET EF>BLT /S>''ES/

To DR! a D,%&ULT Constraint

'o drop a *%


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>LTER T>!LE %e"sons

>LTER Cit+ RO% EF>BLT


>LTER T>!LE %e"sons

>LTER COLBM' Cit+ RO% EF>BLT

SQL CE!TE INDE1 Statement

'"e &+%A'% IN*%K statement is used to create indexes in tables.

Indexes allo t"e database application to find data fast it"out reading t"e "ole table.

#nde/es

An index can be created in a table to find data more quic2ly and efficiently.

'"e users cannot see t"e indexes! t"ey are $ust used to speed up searc"es3queries.

Note:pdating a table it" indexes ta2es more time t"an updating a table it"out (because t"eindexes also need an update). So you s"ould only create indexes on columns (and tables) t"at

ill be frequently searc"ed against.

SQL CE!TE INDE1 Syntax

&reates an index on a table. *uplicate values are alloed/

CRE>TE 'E inde=_name

O' table_name (column_name)

SQL CE!TE )NIQ)E INDE1 Syntax

&reates a unique index on a table. *uplicate values are not alloed/

CRE>TE B'NBE 'E inde=_name



59/107

Note:'"e syntax for creating indexes varies amongst different databases. '"erefore/ &"ec2 t"e

syntax for creating indexes in your database.

CR,&T, #ND, ,/a$)e

'"e SQL statement belo creates an index named 6Index6 on t"e 6LastName6 column in t"e6ersons6 table/

CRE>TE 'E %nde=

O' %e"sons (Last'ame)

If you ant to create an index on a combination of columns! you can list t"e column namesit"in t"e parent"eses! separated by commas/

CRE>TE 'E %nde=O' %e"sons (Last'ame Fi"st'ame)

SQL D#* INDE12 D#* T!%LE2 and D#* D!T!%!SE

Indexes! tables! and databases can easily be deleted3removed it" t"e *+5 statement.

The DR! #ND, State$ent

'"e *+5 IN*%K statement is used to delete an index in a table.

D#* INDE1 Syntax for ,S !ccess

RO% 'E inde=_name O' table_name

D#* INDE1 Syntax for ,S SQL Ser+er

RO% 'E table_nameinde=_name

D#* INDE1 Syntax for D%45#racle

RO% 'E inde=_name

D#* INDE1 Syntax for ,ySQL

>LTER T>!LE table_name RO% 'E inde=_name


60/107

The DR! T&BL, State$ent'"e *+5 'A0L% statement is used to delete a table.

RO% T>!LE table_name

The DR! D&T&B&S, State$ent

'"e *+5 *A'A0AS% statement is used to delete a database.

RO% >T>!>SE database_name

The TRUNC&T, T&BL, State$ent

,"at if e only ant to delete t"e data inside t"e table! and not t"e table itself

'"en! use t"e '+N&A'% 'A0L% statement/

TRB'C>TE T>!LE table_name

SQL !LTE T!%LE Statement

The &LT,R T&BL, State$ent

'"e AL'%+ 'A0L% statement is used to add! delete! or modify columns in an existing table.

SQL !LTE T!%LE Syntax

'o add a column in a table! use t"e folloing syntax/

>LTER T>!LE table_name


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> column_name datat+-e

'o delete a column in a table! use t"e folloing syntax (notice t"at some database systems donCtallo deleting a column)/


RO% COLBM' column_name

'o c"ange t"e data type of a column in a table! use t"e folloing syntax/


>LTER COLBM' column_name datat+-e

SQL &LT,R T&BL, ,/a$)e

Loo2 at t"e 6ersons6 table/





No e ant to add a column named 6*ate5f0irt"6 in t"e 6ersons6 table.


>LTER T>!LE %e"sons

> ateO;!i"t date

Notice t"at t"e ne column! 6*ate5f0irt"6! is of type date and is going to "old a date. '"e datatype specifies "at type of data t"e column can "old.


62/107




Change Data T')e ,/a$)e

No e ant to c"ange t"e data type of t"e column named 6*ate5f0irt"6 in t"e 6ersons6 table.


>LTER T>!LE %e"sons

>LTER COLBM' ateO;!i"t +ea"

Notice t"at t"e 6*ate5f0irt"6 column is no of type year and is going to "old a year in a to1digit or four1digit format.

DR! CLUMN ,/a$)e

Next! e ant to delete t"e column named 6*ate5f0irt"6 in t"e 6ersons6 table.


>LTER T>!LE %e"sons

RO% COLBM' ateO;!i"t

'"e 6ersons6 table ill no li2e t"is/






63/107

SQL !)T# INCE,ENT /ield

Auto1increment allos a unique number to be generated "en a ne record is inserted into a

table.

&UT #NCR,M,NT a %ied

Mery often e ould li2e t"e value of t"e primary 2ey field to be created automatically everytime a ne record is inserted.

,e ould li2e to create an auto1increment field in a table.

S'nta/ +or M'SQL

'"e folloing SQL statement defines t"e 6;Id6 column to be an auto1increment primary 2ey

field in t"e 6ersons6 table/


(

%_d int 'OT 'BLL >BTO_'CREME'T


Fi"st'ame va"ca"(66)>dd"ess va"ca"(66)

Cit+ va"ca"(66)

%RM>R3 &E3 (%_d)

)

-ySQL uses t"e A'5;IN&+%-%N' 2eyord to perform an auto1increment feature.

0y default! t"e starting value for A'5;IN&+%-%N' is 7! and it ill increment by 7 for eac"

ne record.

'o let t"e A'5;IN&+%-%N' sequence start it" anot"er value! use t"e folloing SQL

statement/

>LTER T>!LE %e"sons >BTO_'CREME'T.100


64/107

'o insert a ne record into t"e 6ersons6 table! e ill not "ave to specify a value for t"e 6;Id6

column (a unique value ill be added automatically)/

'SERT 'TO %e"sons (Fi"st'ameLast'ame)

A>LBES (/La"s//Monsen/)

'"e SQL statement above ould insert a ne record into t"e 6ersons6 table. '"e 6;Id6 column

ould be assigned a unique value. '"e 6TE T>!LE %e"sons

(

%_d int %RM>R3 &E3 E'TT3



>dd"ess va"ca"(66)

Cit+ va"ca"(66)

)

'"e -S SQL Server uses t"e I*%N'I'B 2eyord to perform an auto1increment feature.

0y default! t"e starting value for I*%N'I'B is 7! and it ill increment by 7 for eac" ne record.

'o specify t"at t"e 6;Id6 column s"ould start at value 78 and increment by E! c"ange t"e

identity to I*%N'I'B(78!E).

'o insert a ne record into t"e 6ersons6 table! e ill not "ave to specify a value for t"e 6;Id6column (a unique value ill be added automatically)/



'"e SQL statement above ould insert a ne record into t"e 6ersons6 table. '"e 6;Id6 columnould be assigned a unique value. '"e 6


65/107

S'nta/ +or &**ess

'"e folloing SQL statement defines t"e 6;Id6 column to be an auto1increment primary 2ey

field in t"e 6ersons6 table/

CRE>TE T>!LE %e"sons(

%_d %RM>R3 &E3 >BTO'CREME'T



>dd"ess va"ca"(66)

Cit+ va"ca"(66)

)

'"e -S Access uses t"e A'5IN&+%-%N' 2eyord to perform an auto1increment feature.

0y default! t"e starting value for A'5IN&+%-%N' is 7! and it ill increment by 7 for eac"ne record.

'o specify t"at t"e 6;Id6 column s"ould start at value 78 and increment by E! c"ange t"e

autoincrement to A'5IN&+%-%N'(78!E).

'o insert a ne record into t"e 6ersons6 table! e ill not "ave to specify a value for t"e 6;Id6

column (a unique value ill be added automatically)/



'"e SQL statement above ould insert a ne record into t"e 6ersons6 table. '"e 6;Id6 column

ould be assigned a unique value. '"e 6


66/107

M'A>LBE 1

ST>RT ,TH 1

'CREME'T !3 1

C>CHE 10

'"e code above creates a sequence ob$ect called seq;person! t"at starts it" 7 and ill increment

by 7. It ill also cac"e up to 78 values for performance. '"e cac"e option specifies "o many

sequence values ill be stored in memory for faster access.

'o insert a ne record into t"e 6ersons6 table! e ill "ave to use t"e nextval function (t"is

function retrieves t"e next value from seq;person sequence)/

'SERT 'TO %e"sons (%_dFi"st'ameLast'ame)

A>LBES (se7_-e"sonne=tval/La"s//Monsen/)

'"e SQL statement above ould insert a ne record into t"e 6ersons6 table. '"e 6;Id6 columnould be assigned t"e next number from t"e seq;person sequence. '"e 6


67/107

,HERE condition

Note:A vie alays s"os up1to1date data '"e database engine recreates t"e data! using t"evieCs SQL statement! every time a user queries a vie.

SQL CR,&T, #,W ,/a$)es

If you "ave t"e Nort"ind database you can see t"at it "as several vies installed by default.

'"e vie 6&urrent roduct List6 lists all active products (products t"at are not discontinued)

from t"e 6roducts6 table. '"e vie is created it" t"e folloing SQL/

CRE>TE AE, ICu""ent %"oduct ListJ >S

SELECT %"oduct%"oduct'ame

FROM %"oducts,HERE iscontinued.'o

,e can query t"e vie above as follos/

SELECT * FROM ICu""ent %"oduct ListJ

Anot"er vie in t"e Nort"ind sample database selects every product in t"e 6roducts6 table

it" a unit price "ig"er t"an t"e average unit price/

CRE>TE AE, I%"oducts >bove >ve"a#e %"iceJ >S

SELECT %"oduct'ameBnit%"ice

FROM %"oducts

,HERE Bnit%"ice9(SELECT >A:(Bnit%"ice) FROM %"oducts)


SELECT * FROM I%"oducts >bove >ve"a#e %"iceJ

Anot"er vie in t"e Nort"ind database calculates t"e total sale for eac" category in 7O. Notet"at t"is vie selects its data from anot"er vie called 6roduct Sales for 7O6/

CRE>TE AE, ICate#o"+ Sales Fo" 144J >S

SELECT ST'CT Cate#o"+'ameSum(%"oductSales) >S Cate#o"+Sales

FROM I%"oduct Sales ;o" 144J

:ROB% !3 Cate#o"+'ame


68/107


SELECT * FROM ICate#o"+ Sales Fo" 144J

,e can also add a condition to t"e query. No e ant to see t"e total sale only for t"e category

60everages6/

SELECT * FROM ICate#o"+ Sales Fo" 144J

,HERE Cate#o"+'ame./!eve"a#es/

SQL U)dating a ie2

Bou can update a vie by using t"e folloing syntax/

SQL CE!TE # E*L!CE 6IEW Syntax

CRE>TE OR RE%L>CE AE, vie2_name >S


FROM table_name

,HERE condition

No e ant to add t"e 6&ategory6 column to t"e 6&urrent roduct List6 vie. ,e ill update

t"e vie it" t"e folloing SQL/

CRE>TE AE, ICu""ent %"oduct ListJ >S

SELECT %"oduct%"oduct'ameCate#o"+

FROM %"oducts

,HERE iscontinued.'o

SQL Dro))ing a ie2

Bou can delete a vie it" t"e *+5 MI%, command.

SQL D#* 6IEW Syntax

RO% AE, vie2_name


69/107

SQL Date /unctions

SQL Dates'"e most difficult part "en or2ing it" dates is to be sure t"at t"e format of t"e date you

are trying to insert! matc"es t"e format of t"e date column in t"e database.

As long as your data contains only t"e date portion! your queries ill or2 as expected.#oever! if a time portion is involved! it gets complicated.

0efore tal2ing about t"e complications of querying for dates! e ill loo2 at t"e most important

built1in functions for or2ing it" dates.

M'SQL Date %un*tions

'"e folloing table lists t"e most important built1in date functions in -ySQL/

F%nction Description

'O,() Retu"ns te cu""ent date and time

CBR>TE() Retu"ns te cu""ent date

CBRTME() Retu"ns te cu""ent time

>TE() E=t"acts te date -a"t o; a date o" datePtime e=-"ession

ETR>CT() Retu"ns a sin#le -a"t o; a datePtime

>TE_>() >dds a s-eci;ied time inte"val to a date

>TE_SB!() Subt"acts a s-eci;ied time inte"val ;"om a date

>TEFF() Retu"ns te numbe" o; da+s bet2een t2o dates

>TE_FORM>T() is-la+s datePtime data in di;;e"ent ;o"mats

SQL Ser5er Date %un*tions
http://www.w3schools.com/sql/func_now.asphttp://www.w3schools.com/sql/func_curdate.asphttp://www.w3schools.com/sql/func_curtime.asphttp://www.w3schools.com/sql/func_date.asphttp://www.w3schools.com/sql/func_extract.asphttp://www.w3schools.com/sql/func_date_add.asphttp://www.w3schools.com/sql/func_date_sub.asphttp://www.w3schools.com/sql/func_datediff_mysql.asphttp://www.w3schools.com/sql/func_date_format.asphttp://www.w3schools.com/sql/func_now.asphttp://www.w3schools.com/sql/func_curdate.asphttp://www.w3schools.com/sql/func_curtime.asphttp://www.w3schools.com/sql/func_date.asphttp://www.w3schools.com/sql/func_extract.asphttp://www.w3schools.com/sql/func_date_add.asphttp://www.w3schools.com/sql/func_date_sub.asphttp://www.w3schools.com/sql/func_datediff_mysql.asphttp://www.w3schools.com/sql/func_date_format.asp


70/107

'"e folloing table lists t"e most important built1in date functions in SQL Server/

F%nction Description

:ET>TE() Retu"ns te cu""ent date and time

>TE%>RT() Retu"ns a sin#le -a"t o; a datePtime

>TE>() >dds o" subt"acts a s-eci;ied time inte"val ;"om a date

>TEFF() Retu"ns te time bet2een t2o dates

CO'AERT() is-la+s datePtime data in di;;e"ent ;o"mats

SQL Date Data T')es

M'SQLcomes it" t"e folloing data types for storing a date or a date3time value in t"e

database/

>TE Q ;o"mat 3333QMMQ

>TETME Q ;o"mat 3333QMMQ HHMMSS

TMEST>M% Q ;o"mat 3333QMMQ HHMMSS

3E>R Q ;o"mat 3333 o" 33

SQL Ser5ercomes it" t"e folloing data types for storing a date or a date3time value in t"edatabase/

>TE Q ;o"mat 3333QMMQ

>TETME Q ;o"mat 3333QMMQ HHMMSS

SM>LL>TETME Q ;o"mat 3333QMMQ HHMMSS

TMEST>M% Q ;o"mat a uni7ue numbe"

Note:'"e date types are c"osen for a column "en you create a ne table in your database


71/107

Assume e "ave t"e folloing 65rders6 table/

OrderId Prod%ctName OrderDate

1 :eitost 00Q11Q11

Camembe"t %ie""ot 00Q11Q04

$ Moa"ella di :iovanni 00Q11Q11

@ Masca"-one Fabioli 00Q10Q4

No e ant to select t"e records it" an 5rder*ate of 6488P1771776 from t"e table above.


SELECT * FROM O"de"s ,HERE O"de"ate./00Q11Q11/



1 :eitost 00Q11Q11

$ Moa"ella di :iovanni 00Q11Q11

No! assume t"at t"e 65rders6 table loo2s li2e t"is (notice t"e time component in t"e

65rder*ate6 column)/


1 :eitost 00Q11Q11 1$$@@

Camembe"t %ie""ot 00Q11Q04 16@61

$ Moa"ella di :iovanni 00Q11Q11 11101

@ Masca"-one Fabioli 00Q10Q4 1@6564

If e use t"e same S%L%&' statement as above/

SELECT * FROM O"de"s ,HERE O"de"ate./00Q11Q11/


72/107

e ill get no result '"is is because t"e query is loo2ing only for dates it" no time portion.

Ti):If you ant to 2eep your queries simple and easy to maintain! do not allo time

components in your dates

SQL N)LL 6alues

NLL values represent missing un2non data.

0y default! a table column can "old NLL values.

'"is c"apter ill explain t"e IS NLL and IS N5' NLL operators.

SQL NULL aues

If a column in a table is optional! e can insert a ne record or update an existing record it"out

adding a value to t"is column. '"is means t"at t"e field ill be saved it" a NLL value.

NLL values are treated differently from ot"er values.

NLL is used as a place"older for un2non or inapplicable values.

Note:It is not possible to compare NLL and 8 t"ey are not equivalent.

SQL Wor=ing 2ith NULL aues

Loo2 at t"e folloing 6ersons6 table/


1 Hansen Ola Sandnes


$ %ette"sen &a"i Stavan#e"

Suppose t"at t"e 6Address6 column in t"e 6ersons6 table is optional. '"is means t"at if e

insert a record it" no value for t"e 6Address6 column! t"e 6Address6 column ill be saved it"

a NLL value.


73/107

#o can e test for NLL values

It is not possible to test for NLL values it" comparison operators! suc" as @! >! or >?.

,e ill "ave to use t"e IS NLL and IS N5' NLL operators instead.

SQL #S NULL

#o do e select only t"e records it" NLL values in t"e 6Address6 column

,e ill "ave to use t"e IS NLL operator/

SELECT Last'ameFi"st'ame>dd"ess FROM %e"sons

,HERE >dd"ess S 'BLL


LastName FirstName Address

Hansen Ola

%ette"sen &a"i

Ti):Alays use IS NLL to loo2 for NLL values.

SQL #S NT NULL

#o do e select only t"e records it" no NLL values in t"e 6Address6 column

,e ill "ave to use t"e IS N5' NLL operator/

SELECT Last'ameFi"st'ame>dd"ess FROM %e"sons

,HERE >dd"ess S 'OT 'BLL


LastName FirstName Address

Svendson Tove !o"#vn $


74/107

In t"e next c"apter e ill loo2 at t"e ISNLL()! NML()! I


75/107

ra*e

5racle does not "ave an ISNLL() function. #oever! e can use t"e NML() function to

ac"ieve t"e same result/

SELECT %"oduct'ameBnit%"ice*(BnitsnStoc


76/107

nte#e" >llo2s 2ole numbe"s bet2een Q$5 and $5 b+tes

Lon# >llo2s 2ole numbe"s bet2een Q1@@$5@ and 1@@$5@ @ b+tes

Sin#le Sin#le -"ecision ;loatin#Q-oint ,ill andle most decimals @ b+tes

ouble ouble -"ecision ;loatin#Q-oint ,ill andle most decimals b+tes

Cu""enc+ Bse ;o" cu""enc+ Holds u- to 16 di#its o; 2ole dolla"s -lus @

decimal -laces Tip)3ou can coose 2ic count"+/s cu""enc+ to

use

b+tes

>uto'umbe" >uto'umbe" ;ields automaticall+ #ive eac "eco"d its o2n numbe"

usuall+ sta"tin# at 1

@ b+tes

atePTime Bse ;o" dates and times b+tes

3esP'o > lo#ical ;ield can be dis-la+ed as 3esP'o T"uePFalse o" OnPO;;

n code use te constants T"ue and False (e7uivalent to Q1 and 0)

Note)'ull values a"e not allo2ed in 3esP'o ;ields

1 bit

Ole Obect Can sto"e -ictu"es audio video o" ote" !LO!s (!ina"+ La"#e

O!ects)

u- to

1:!

H+-e"lin< Contain linR(sie) Holds a ;i=ed len#t st"in# (can contain lette"s numbe"s and s-ecial

ca"acte"s) Te ;i=ed sie is s-eci;ied in -a"entesis Can sto"e u- to 66

ca"acte"s

A>RCH>R(sie) Holds a va"iable len#t st"in# (can contain lette"s numbe"s and s-ecial


77/107

ca"acte"s) Te ma=imum sie is s-eci;ied in -a"entesis Can sto"e u- to

66 ca"acte"s Note); +ou -ut a #"eate" value tan 66 it 2ill be conve"ted

to a TET t+-e

T'3TET Holds a st"in# 2it a ma=imum len#t o; 66 ca"acte"s

TET Holds a st"in# 2it a ma=imum len#t o; 566$6 ca"acte"s

!LO! Fo" !LO!s (!ina"+ La"#e O!ects) Holds u- to 566$6 b+tes o; data

MEBMTET Holds a st"in# 2it a ma=imum len#t o; 1516 ca"acte"s

MEBM!LO! Fo" !LO!s (!ina"+ La"#e O!ects) Holds u- to 1516 b+tes o; data

LO':TET Holds a st"in# 2it a ma=imum len#t o; @4@4546 ca"acte"s

LO':!LO! Fo" !LO!s (!ina"+ La"#e O!ects) Holds u- to @4@4546 b+tes o; data

E'BM(=+etc) Let +ou ente" a list o; -ossible values 3ou can list u- to 566$6 values in an

E'BM list ; a value is inse"ted tat is not in te list a blan< value 2ill be

inse"ted

Note:'"e values are sorted in t"e order you enter t"em.

Bou enter t"e possible values in t"is format/ %N-(CKC!CBC!CRC)

SET Simila" to E'BM e=ce-t tat SET ma+ contain u- to 5@ list items and can

sto"e mo"e tan one coice

Nu$ber t')es:

Data type Description

T'3'T(sie) Q1 to 1 no"mal 0 to 66 B'S:'E* Te ma=imum numbe" o; di#its

ma+ be s-eci;ied in -a"entesis

SM>LL'T(sie) Q$5 to $5 no"mal 0 to 566$6 B'S:'E* Te ma=imum numbe" o;

di#its ma+ be s-eci;ied in -a"entesis

MEBM'T(sie) Q$50 to $50 no"mal 0 to 1516 B'S:'E* Te ma=imumnumbe" o; di#its ma+ be s-eci;ied in -a"entesis

'T(sie) Q1@@$5@ to 1@@$5@ no"mal 0 to @4@4546 B'S:'E* Te

ma=imum numbe" o; di#its ma+ be s-eci;ied in -a"entesis

!:'T(sie) Q4$$0$56@60 to 4$$0$56@60 no"mal 0 to

1@@5@@0$04661516 B'S:'E* Te ma=imum numbe" o; di#its ma+


78/107

be s-eci;ied in -a"entesis

FLO>T(sied) > small numbe" 2it a ;loatin# decimal -oint Te ma=imum numbe" o; di#its

ma+ be s-eci;ied in te sie -a"amete" Te ma=imum numbe" o; di#its to te

"i#t o; te decimal -oint is s-eci;ied in te d -a"amete"

OB!LE(sied) > la"#e numbe" 2it a ;loatin# decimal -oint Te ma=imum numbe" o; di#its

ma+ be s-eci;ied in te sie -a"amete" Te ma=imum numbe" o; di#its to te

"i#t o; te decimal -oint is s-eci;ied in te d -a"amete"

ECM>L(sied) > OB!LE sto"ed as a st"in# allo2in# ;o" a ;i=ed decimal -oint Te

ma=imum numbe" o; di#its ma+ be s-eci;ied in te sie -a"amete" Te

ma=imum numbe" o; di#its to te "i#t o; te decimal -oint is s-eci;ied in te

d -a"amete"

='"e integer types "ave an extra option called NSIJN%*. Normally! t"e integer goes from annegative to positive value. Adding t"e NSIJN%* attribute ill move t"at range up so it starts

at ero instead of a negative number.

Date t')es:


>TE() > date Fo"mat 3333QMMQ

Note:'"e supported range is from C7888187187C to C174197C

>TETME() *> date and time combination Fo"mat 3333QMMQ HHMMSS

Note:'"e supported range is from C7888187187 88/88/88C to C17419749/E/EC

TMEST>M%() *> timestam- TMEST>M% values a"e sto"ed as te numbe" o; seconds

since te Bni= e-oc (/140Q01Q01 000000/ BTC) Fo"mat 3333QMMQ

HHMMSS

Note:'"e supported range is from C7O8187187 88/88/87C '& to C489P1871

8 89/7/8OC '&

TME() > time Fo"mat HHMMSS

Note:'"e supported range is from C1P9P/E/EC to CP9P/E/EC

3E>R() > +ea" in t2oQdi#it o" ;ou"Qdi#it ;o"mat

Note:Malues alloed in four1digit format/ 787 to 47EE. Malues alloed in

to1digit format/ O8 to T! representing years from 7O8 to 48T


79/107

=%ven if *A'%'I-% and 'I-%S'A- return t"e same format! t"ey or2 very differently. In

an INS%+' or *A'% query! t"e 'I-%S'A- automatically set itself to t"e current date and

time. 'I-%S'A- also accepts various formats! li2e BBBB--**##--SS!BB--**##--SS! BBBB--**! or BB--**.

SQL Ser5er Data T')es

Chara*ter strings:

Data type Description &tora(e

ca"(n) Fi=edQlen#t ca"acte" st"in# Ma=imum 000 ca"acte"s n

va"ca"(n) Aa"iableQlen#t ca"acte" st"in# Ma=imum 000 ca"acte"s

va"ca"(ma=) Aa"iableQlen#t ca"acte" st"in# Ma=imum 10$@1@

ca"acte"s

te=t Aa"iableQlen#t ca"acte" st"in# Ma=imum :! o; te=t data

Uni*ode strings:


nca"(n) Fi=edQlen#t Bnicode data Ma=imum @000 ca"acte"s

nva"ca"(n) Aa"iableQlen#t Bnicode data Ma=imum @000 ca"acte"s

nva"ca"(ma=) Aa"iableQlen#t Bnicode data Ma=imum 6$5041 ca"acte"s

nte=t Aa"iableQlen#t Bnicode data Ma=imum :! o; te=t data

Binar' t')es:


bit >llo2s 0 1 o" 'BLL

bina"+(n) Fi=edQlen#t bina"+ data Ma=imum 000 b+tes

va"bina"+(n) Aa"iableQlen#t bina"+ data Ma=imum 000 b+tes

va"bina"+(ma=) Aa"iableQlen#t bina"+ data Ma=imum :!


80/107

ima#e Aa"iableQlen#t bina"+ data Ma=imum :!

Nu$ber t')es:


tin+int >llo2s 2ole numbe"s ;"om 0 to 66 1 b+te

smallint >llo2s 2ole numbe"s bet2een Q$5 and $5 b+tes

int >llo2s 2ole numbe"s bet2een Q1@@$5@ and 1@@$5@ @ b+tes

bi#int >llo2s 2ole numbe"s bet2een Q4$$0$56@60 and

4$$0$56@60

b+tes

decimal(-s) Fi=ed -"ecision and scale numbe"s

Allos numbers from 178U9P V7 to 78U9P W7.

'"e p parameter indicates t"e maximum total number of digits t"at

can be stored (bot" to t"e left and to t"e rig"t of t"e decimal point).p must be a value from 7 to 9P. *efault is 7P.

'"e s parameter indicates t"e maximum number of digits stored to

t"e rig"t of t"e decimal point. s must be a value from 8 to p. *efault

value is 8

6Q1

b+tes

nume"ic(-s) Fi=ed -"ecision and scale numbe"s

Allos numbers from 178U9P V7 to 78U9P W7.

'"e p parameter indicates t"e maximum total number of digits t"atcan be stored (bot" to t"e left and to t"e rig"t of t"e decimal point).

p must be a value from 7 to 9P. *efault is 7P.

'"e s parameter indicates t"e maximum number of digits stored to

t"e rig"t of t"e decimal point. s must be a value from 8 to p. *efaultvalue is 8

6Q1b+tes

smallmone+ Moneta"+ data ;"om Q1@@$5@ to 1@@$5@ @ b+tes

mone+ Moneta"+ data ;"om Q4$$0$56@60 to

4$$0$56@60

b+tes

;loat(n) Floatin# -"ecision numbe" data ;"om Q14E $0 to 14E $0

'"e n parameter indicates "et"er t"e field s"ould "old or P

@ o"

b+tes


81/107

bytes. float(4) "olds a 1byte field and float(E9) "olds an P1bytefield. *efault value of n is E9.

"eal Floatin# -"ecision numbe" data ;"om Q$@0E $ to $@0E $ @ b+tes

Date t')es:


datetime F"om Danua"+ 1 16$ to ecembe" $1 4444 2it an accu"ac+ o;

$$$ milliseconds

b+tes

datetime F"om Danua"+ 1 0001 to ecembe" $1 4444 2it an accu"ac+ o;

100 nanoseconds

5Q b+tes

smalldatetime F"om Danua"+ 1 1400 to Dune 5 04 2it an accu"ac+ o; 1minute

@ b+tes

date Sto"e a date onl+ F"om Danua"+ 1 0001 to ecembe" $1 4444 $ b+tes

time Sto"e a time onl+ to an accu"ac+ o; 100 nanoseconds $Q6 b+tes

datetimeo;;set Te same as datetime 2it te addition o; a time one o;;set Q10

b+tes

timestam- Sto"es a uni7ue numbe" tat #ets u-dated eve"+ time a "o2 #ets

c"eated o" modi;ied Te timestam- value is based u-on an inte"nal

cloc< and does not co""es-ond to "eal time Eac table ma+ ave

onl+ one timestam- va"iable

ther data t')es:


s7l_va"iant Sto"es u- to 000 b+tes o; data o; va"ious data t+-es e=ce-t te=t nte=t and

timestam-

uni7ueidenti;ie" Sto"es a #loball+ uni7ue identi;ie" (:B)

=ml Sto"es ML ;o"matted data Ma=imum :!

cu"so" Sto"es a "e;e"ence to a cu"so" used ;o" database o-e"ations

table Sto"es a "esultQset ;o" late" -"ocessin#


82/107

SQL /unctions

SQL "as many built1in functions for performing calculations on data.

SQL &ggregate %un*tions

SQL aggregate functions return a single value! calculated from values in a column.

seful aggregate functions/

>A:() Q Retu"ns te ave"a#e value COB'T() Q Retu"ns te numbe" o; "o2s

FRST() Q Retu"ns te ;i"st value

L>ST() Q Retu"ns te last value

M>() Q Retu"ns te la"#est value

M'() Q Retu"ns te smallest value

SBM() Q Retu"ns te sum

SQL S*aar +un*tions

SQL scalar functions return a single value! based on t"e input value.

seful scalar functions/

BC>SE() Q Conve"ts a ;ield to u--e" case

LC>SE() Q Conve"ts a ;ield to lo2e" case

M() Q E=t"act ca"acte"s ;"om a te=t ;ield

LE'() Q Retu"ns te len#t o; a te=t ;ield

ROB'() Q Rounds a nume"ic ;ield to te numbe" o; decimals s-eci;ied

'O,() Q Retu"ns te cu""ent s+stem date and time

FORM>T() Q Fo"mats o2 a ;ield is to be dis-la+ed


83/107

Ti):'"e aggregate functions and t"e scalar functions ill be explained in details in t"e next

c"apters.

SQL !6078 /unction

The &;@A %un*tion

'"e AMJ() function returns t"e average value of a numeric column.

SQL !6078 Syntax

SELECT >A:(column_name) FROM table_name

SQL &;@A ,/a$)e

,e "ave t"e folloing 65rders6 table/

O_Id OrderDate OrderPrice C%stomer

1 00P11P1 1000 Hansen

00P10P$ 1500 'ilsen

$ 00P04P0 00 Hansen

@ 00P04P0$ $00 Hansen

6 00P0P$0 000 Densen

5 00P10P0@ 100 'ilsen

No e ant to find t"e average value of t"e 65rderrice6 fields.


SELECT >A:(O"de"%"ice) >S O"de">ve"a#e FROM O"de"s



84/107

OrderA*era(e

460

No e ant to find t"e customers t"at "ave an 5rderrice value "ig"er t"an t"e average5rderrice value.


SELECT Custome" FROM O"de"s

,HERE O"de"%"ice9(SELECT >A:(O"de"%"ice) FROM O"de"s)


C%stomer

Hansen

'ilsen

Densen

SQL C#)NT78 /unction

'"e &5N'() function returns t"e number of ros t"at matc"es a specified criteria.

SQL C#)NT7column9name8 Syntax

'"e &5N'(column;name) function returns t"e number of values (NLL values ill not be

counted) of t"e specified column/

SELECT COB'T(column_name) FROM table_name

SQL C#)NT7:8 Syntax

'"e &5N'(=) function returns t"e number of records in a table/

SELECT COB'T(*) FROM table_name


85/107

SQL C#)NT7DISTINCT column9name8 Syntax

'"e &5N'(*IS'IN&' column;name) function returns t"e number of distinct values of t"e

specified column/

SELECT COB'T(ST'CT column_name) FROM table_name

Note:&5N'(*IS'IN&') or2s it" 5+A&L% and -icrosoft SQL Server! but not it"

-icrosoft Access.

SQL CUNT@*ou$n"na$eA ,/a$)e



1 00P11P1 1000 Hansen

00P10P$ 1500 'ilsen

$ 00P04P0 00 Hansen

@ 00P04P0$ $00 Hansen


5 00P10P0@ 100 'ilsen

No e ant to count t"e number of orders from 6&ustomer Nilsen6.


SELECT COB'T(Custome") >S Custome"'ilsen FROM O"de"s

,HERE Custome"./'ilsen/

'"e result of t"e SQL statement above ill be 4! because t"e customer Nilsen "as made 4 ordersin total/

C%stomerNilsen


86/107

SQL CUNT@0A ,/a$)e

If e omit t"e ,#%+% clause! li2e t"is/

SELECT COB'T(*) >S 'umbe"O;O"de"s FROM O"de"s


N%m+erO"Orders

5

"ic" is t"e total number of ros in t"e table.

SQL CUNT@D#ST#NCT *ou$n"na$eA ,/a$)e

No e ant to count t"e number of unique customers in t"e 65rders6 table.


SELECT COB'T(ST'CT Custome") >S 'umbe"O;Custome"s FROM O"de"s


N%m+erO"C%stomers

$

"ic" is t"e number of unique customers (#ansen! Nilsen! and Densen) in t"e 65rders6 table.

SQL /IST78 /unction

The %#RST@A %un*tion

'"e


87/107

SQL /IST78 Syntax

SELECT FRST(column_name) FROM table_name

SQL %#RST@A ,/a$)e



1 00P11P1 1000 Hansen

00P10P$ 1500 'ilsen

$ 00P04P0 00 Hansen

@ 00P04P0$ $00 Hansen


5 00P10P0@ 100 'ilsen

No e ant to find t"e first value of t"e 65rderrice6 column.


SELECT FRST(O"de"%"ice) >S Fi"stO"de"%"ice FROM O"de"s

Ti):,or2around if


88/107

SQL L!ST78 /unction

The L&ST@A %un*tion'"e LAS'() function returns t"e last value of t"e selected column.

SQL L!ST78 Syntax

SELECT L>ST(column_name) FROM table_name

SQL L&ST@A ,/a$)e



1 00P11P1 1000 Hansen

00P10P$ 1500 'ilsen

$ 00P04P0 00 Hansen

@ 00P04P0$ $00 Hansen


5 00P10P0@ 100 'ilsen

No e ant to find t"e last value of t"e 65rderrice6 column.


SELECT L>ST(O"de"%"ice) >S LastO"de"%"ice FROM O"de"s

Ti):,or2around if LAS'() function is not supported/

SELECT O"de"%"ice FROM O"de"s ORER !3 O_d ESC LMT 1



89/107

LastOrderPrice

100

SQL ,!178 /unction

The M&@A %un*tion

'"e -AK() function returns t"e largest value of t"e selected column.

SQL ,!178 Syntax

SELECT M>(column_name) FROM table_name

SQL M&@A ,/a$)e



1 00P11P1 1000 Hansen

00P10P$ 1500 'ilsen

$ 00P04P0 00 Hansen

@ 00P04P0$ $00 Hansen


5 00P10P0@ 100 'ilsen

No e ant to find t"e largest value of t"e 65rderrice6 column.


SELECT M>(O"de"%"ice) >S La"#estO"de"%"ice FROM O"de"s


90/107


Lar(estOrderPrice

000

SQL ,IN78 /unction

The M#N@A %un*tion

'"e -IN() function returns t"e smallest value of t"e selected column.

SQL ,IN78 Syntax

SELECT M'(column_name) FROM table_name

SQL M#N@A ,/a$)e



1 00P11P1 1000 Hansen

00P10P$ 1500 'ilsen

$ 00P04P0 00 Hansen

@ 00P04P0$ $00 Hansen


5 00P10P0@ 100 'ilsen

No e ant to find t"e smallest value of t"e 65rderrice6 column.



91/107

SELECT M'(O"de"%"ice) >S SmallestO"de"%"ice FROM O"de"s


&mallestOrderPrice

100

SQL S),78 /unction

The SUM@A %un*tion

'"e S-() function returns t"e total sum of a numeric column.

SQL S),78 Syntax

SELECT SBM(column_name) FROM table_name

SQL SUM@A ,/a$)e



1 00P11P1 1000 Hansen

00P10P$ 1500 'ilsen

$ 00P04P0 00 Hansen

@ 00P04P0$ $00 Hansen


5 00P10P0@ 100 'ilsen

No e ant to find t"e sum of all 65rderrice6 fields6.


92/107


SELECT SBM(O"de"%"ice) >S O"de"Total FROM O"de"s


OrderTotal

600

SQL 0#)* %& Statement

Aggregate functions often need an added J+5 0B statement.

The ;RU! BY State$ent

'"e J+5 0B statement is used in con$unction it" t"e aggregate functions to group t"e

result1set by one or more columns.

SQL 0#)* %& Syntax

SELECT column_name a##"e#ate_;unction(column_name)FROM table_name

,HERE column_name o-e"ato" value

:ROB% !3 column_name

SQL ;RU! BY ,/a$)e



1 00P11P1 1000 Hansen

00P10P$ 1500 'ilsen

$ 00P04P0 00 Hansen


93/107

@ 00P04P0$ $00 Hansen


5 00P10P0@ 100 'ilsen

No e ant to find t"e total sum (total order) of eac" customer.

,e ill "ave to use t"e J+5 0B statement to group t"e customers.


SELECT Custome"SBM(O"de"%"ice) FROM O"de"s

:ROB% !3 Custome"


C%stomer &!,-OrderPrice.

Hansen 000

'ilsen 100

Densen 000

Nice IsnCt it /)

LetCs see "at "appens if e omit t"e J+5 0B statement/




Hansen 600

'ilsen 600

Hansen 600

Hansen 600


94/107

Densen 600

'ilsen 600

'"e result1set above is not "at e anted.

,/)anation o+ 2h' the abo5e S,L,CT state$ent *annot be used:'"e S%L%&' statement

above "as to columns specified (&ustomer and S-(5rderrice). '"e 6S-(5rderrice)6

returns a single value (t"at is t"e total sum of t"e 65rderrice6 column)! "ile 6&ustomer6returns T values (one value for eac" ro in t"e 65rders6 table). '"is ill t"erefore not give us t"e

correct result. #oever! you "ave seen t"at t"e J+5 0B statement solves t"is problem.

;RU! BY More Than ne Cou$n

,e can also use t"e J+5 0B statement on more t"an one column! li2e t"is/

SELECT Custome"O"de"ateSBM(O"de"%"ice) FROM O"de"s

:ROB% !3 Custome"O"de"ate

SQL H!6IN0 Clause

The 1N; Cause

'"e #AMINJ clause as added to SQL because t"e ,#%+% 2eyord could not be used it"

aggregate functions.

SQL H!6IN0 Syntax

SELECT column_name a##"e#ate_;unction(column_name)

FROM table_name



H>A': a##"e#ate_;unction(column_name) o-e"ato" value

SQL 1N; ,/a$)e


95/107



1 00P11P1 1000 Hansen

00P10P$ 1500 'ilsen

$ 00P04P0 00 Hansen

@ 00P04P0$ $00 Hansen


5 00P10P0@ 100 'ilsen

No e ant to find if any of t"e customers "ave a total order of less t"an 4888.



:ROB% !3 Custome"

H>A': SBM(O"de"%"ice)8000



'ilsen 100

No e ant to find if t"e customers 6#ansen6 or 6Densen6 "ave a total order of more t"an

7E88.

,e add an ordinary ,#%+% clause to t"e SQL statement/


,HERE Custome"./Hansen/ OR Custome"./Densen/:ROB% !3 Custome"

H>A': SBM(O"de"%"ice)91600




96/107

Hansen 000

Densen 000

SQL )C!SE78 /unction

The UC&S,@A %un*tion

'"e &AS%() function converts t"e value of a field to uppercase.

SQL )C!SE78 Syntax

SELECT BC>SE(column_name) FROM table_name

Syntax for SQL Ser+er

SELECT B%%ER(column_name) FROM table_name

SQL UC&S,@A ,/a$)e






No e ant to select t"e content of t"e 6LastName6 and 6


97/107


LastName FirstName

H>'SE' Ola

SAE'SO' Tove

%ETTERSE' &a"i

SQL LC!SE78 /unction

The LC&S,@A %un*tion

'"e L&AS%() function converts t"e value of a field to loercase.

SQL LC!SE78 Syntax

SELECT LC>SE(column_name) FROM table_name

Syntax for SQL Ser+erSELECT LO,ER(column_name) FROM table_name

SQL LC&S,@A ,/a$)e







98/107

No e ant to select t"e content of t"e 6LastName6 and 6


99/107






No e ant to extract t"e first four c"aracters of t"e 6&ity6 column above.


SELECT M(Cit+1@) as SmallCit+ FROM %e"sons


&mallCity

Sand

Sand

Stav

SQL LEN78 /unction

The L,N@A %un*tion

'"e L%N() function returns t"e lengt" of t"e value in a text field.

SQL LEN78 SyntaxSELECT LE'(column_name) FROM table_name

SQL L,N@A ,/a$)e


100/107






No e ant to select t"e lengt" of t"e values in t"e 6Address6 column above.


SELECT LE'(>dd"ess) as Len#tO;>dd"ess FROM %e"sons


Len(t$O"Address

1

4

4

SQL #)ND78 /unction

The RUND@A %un*tion

'"e +5N*() function is used to round a numeric field to t"e number of decimals specified.

SQL #)ND78 SyntaxSELECT ROB'(column_namedecimals) FROM table_name

Parameter Description

column_name Re7ui"ed Te ;ield to "ound


101/107

decimals Re7ui"ed S-eci;ies te numbe" o; decimals to be "etu"ned

SQL RUND@A ,/a$)e

,e "ave t"e folloing 6roducts6 table/

Prod_Id Prod%ctName !nit !nitPrice

1 Da"lsbe"# 1000 # 10@6

Masca"-one 1000 # $65

$ :o"#onola 1000 # 165

No e ant to display t"e product name and t"e price rounded to t"e nearest integer.


SELECT %"oduct'ame ROB'(Bnit%"ice0) as Bnit%"ice FROM %"oducts


Prod%ctName !nitPrice

Da"lsbe"# 10

Masca"-one $$

:o"#onola 15

SQL N#W78 /unction

The NW@A %un*tion

'"e N5,() function returns t"e current system date and time.


102/107

SQL N#W78 Syntax

SELECT 'O,() FROM table_name

SQL NW@A ,/a$)e



1 Da"lsbe"# 1000 # 10@6

Masca"-one 1000 # $65

$ :o"#onola 1000 # 165

No e ant to display t"e products and prices per todayCs date.


SELECT %"oduct'ame Bnit%"ice 'o2() as %e"ate FROM %"oducts


Prod%ctName !nitPrice PerDate

Da"lsbe"# 10@6 10PP00 1160 >M

Masca"-one $65 10PP00 1160 >M

:o"#onola 165 10PP00 1160 >M

SQL /#,!T78 /unction

The %RM&T@A %un*tion

'"e


103/107

SQL /#,!T78 Syntax

SELECT FORM>T(column_name;o"mat) FROM table_name

Parameter Description

column_name Re7ui"ed Te ;ield to be ;o"matted

;o"mat Re7ui"ed S-eci;ies te ;o"mat

SQL %RM&T@A ,/a$)e



1 Da"lsbe"# 1000 # 10@6

Masca"-one 1000 # $65

$ :o"#onola 1000 # 165

No e ant to display t"e products and prices per todayCs date (it" todayCs date displayed int"e folloing format 6BBBB1--1**6).


SELECT %"oduct'ame Bnit%"ice FORM>T('o2()/3333QMMQ/) as %e"ate

FROM %"oducts


Prod%ctName !nitPrice PerDate

Da"lsbe"# 10@6 00Q10Q0

Masca"-one $65 00Q10Q0

:o"#onola 165 00Q10Q0


104/107

SQL Quic; eference /rom W3Schools

&/L &tatement &ynta0

>' P OR SELECT column_name(s)

FROM table_name

,HERE condition

>'?OR condition

>LTER T>!LE >LTER T>!LE table_name

> column_name datat+-e

or

AL'%+ 'A0L% table;name*+5 &5L-N column;name

>S (alias) SELECT column_name >S column_alias

FROM table_name

or

S%L%&' column;name

' value

CRE>TE >T>!>SE CRE>TE >T>!>SE database_name

CRE>TE T>!LE CRE>TE T>!LE table_name

(

column_name1 data_t+-e

column_name data_t+-e

column_name data_t+-e

)

CRE>TE 'E CRE>TE 'E inde=_name


or


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&+%A'% NIQ% IN*%K index;name5N table;name (column;name)

CRE>TE AE, CRE>TE AE, vie2_name >S


FROM table_name

,HERE condition

ELETE ELETE FROM table_name

,HERE some_column.some_value

or

*%L%'% T>!>SE RO% >T>!>SE database_name

RO% 'E RO% 'E table_nameinde=_name (SNL Se"ve")

RO% 'E inde=_name O' table_name (MS >ccess)

RO% 'E inde=_name (!PO"acle)


RO% 'E inde=_name (M+SNL)

RO% T>!LE RO% T>!LE table_name

:ROB% !3 SELECT column_name a##"e#ate_;unction(column_name)

FROM table_name



H>A': SELECT column_name a##"e#ate_;unction(column_name)

FROM table_name



H>A': a##"e#ate_;unction(column_name) o-e"ato" value

' SELECT column_name(s)

FROM table_name

,HERE column_name

' (value1value)

'SERT 'TO 'SERT 'TO table_name


106/107


or

INS%+' IN'5 table;name

(column7! column4! column9!...)MAL%S (value7! value4! value9!....)

''ER DO' SELECT column_name(s)

FROM table_name1

''ER DO' table_name


LEFT DO' SELECT column_name(s)

FROM table_name1

LEFT DO' table_name


R:HT DO' SELECT column_name(s)

FROM table_name1

R:HT DO' table_name


FBLL DO' SELECT column_name(s)

FROM table_name1

FBLL DO' table_name


L&E SELECT column_name(s)FROM table_name

,HERE column_name L&E -atte"n

ORER !3 SELECT column_name(s)

FROM table_name

ORER !3 column_name I>SC?ESCJ

SELECT SELECT column_name(s)

FROM table_name

SELECT * SELECT *FROM table_name

SELECT ST'CT SELECT ST'CT column_name(s)

FROM table_name

SELECT 'TO SELECT *

'TO ne2_table_name I' e=te"naldatabaseJ


107/107

FROM old_table_name

or

S%L%&' column;name(s)

IN'5 ne;table;name GIN externaldatabaseHTE T>!LE table_name

B'O' SELECT column_name(s) FROM table_name1

B'O'

SELECT co

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