sql sat cambridge - mdx 101 - 20130928

7/27/2019 SQL Sat Cambridge - MDX 101 - 20130928

1/37

Alex Whittles

[email protected]

PurpleFrogSystems.comPurpleFrogSystems.com/blog

Twitter: @Pu

rpleFrogSys

MDX 101

Now its Multi-Dimensional
mailto:[email protected]://www.purplefrogsystems.com/http://www.purplefrogsystems.com/bloghttp://localhost/var/www/apps/conversion/tmp/scratch_6/Twitter.com/PurpleFrogSyshttp://localhost/var/www/apps/conversion/tmp/scratch_6/Twitter.com/PurpleFrogSyshttp://localhost/var/www/apps/conversion/tmp/scratch_6/Twitter.com/PurpleFrogSyshttp://www.purplefrogsystems.com/bloghttp://www.purplefrogsystems.com/mailto:[email protected]


2/37

Alex Whittles

Business Intelligence ConsultancyData Warehousing Data Quality

OLAP Cubes ETL Systems

Dimensional Modelling Reporting Systems

PASS Chapter Leader in Birmingham, UK

www.SQLMidlands.com

Regular speaker at SQL Bits, SQL Relay, SQL

Saturday, Webinars & PASS Chapters

Run Purple Frog BI Consultancy

MSc in Business Intelligence
http://www.sqlmidlands.com/http://www.sqlmidlands.com/


3/37

Location Date

Reading Mon 11th November

Southampton Tue 12th November

Cardiff Wed 13th November

Birmingham Thu 14th

NovemberHemel Hempstead Fri 15th November

Newcastle Mon 25th November

Manchester Tue 26th November

Norwich Wed 27th November

Bristol Thu 28th November

London Fri 29th November

SQLRelay.co.uk


4/37

What is MDX?

Query Language

Used to query OLAP Cubes

Love child of SQL and a Rubiks Cube


5/37

SQL vs MDX

SELECT CurrencyName, OrderDateKey, OrderQuantity

FROM FactInternetSales fis

INNER JOIN dbo.DimCurrency dc

ON fis.CurrencyKey = dc.CurrencyKey


6/37

SQL vs MDX

SELECT

[Currency].[Currency].MEMBERS ON COLUMNS,

[Date].[Calendar].[Year].MEMBERS ON ROWS

FROM [Adventure Works]WHERE [Measures].[Internet Order Count]


7/37

Cube Basics

SQL

Server

SSIS

Integration Services

SSRS

Reporting Services

SSAS

Analysis Services

Query using: Excel SSRS

PerformancePoint

MDX

Other tools


8/37

Cube Basics

Finance

Database

Sales

Database

Marketing

XLS3rd Party CSV

Data

Warehouse

Cube

Reports


9/37

Cube Benefits

Speed

Simplicity

Business Calculation Logic

Drag & Drop

Power of MDX


10/37

Dimensions Vs Measures

Dimensions

Usually text

Things you group or filter by

A number of attributes

Measures

Always numbers

Things you add up


11/37

The Star Schema

Measures

Dimension

DimensionDimension

Dimension


12/37

MDX Basics Query Structure

SELECT { SET } ON COLUMNS,

{ SET } ON ROWSFROM CUBE

WHERE ( TUPLE )


13/37


14/37

SetSetTuple

MDX Basics Cheat Sheet

MDX SQL Equivalent (ish) Syntax

Measure Column (numeric) [Measures].[xxx]

Dimension Table [Dimension]

Attribute Column (text) [Dimension].[Attribute]

Hierarchy GROUP BY Col1, Col2 [Dimension].[Hierarchy]

Member Row[Dimension].[Attribute].[Member]

[Dimension].[Hierarchy].[Member]

Tuple Multiple WHEREs ( Member, Member, Member, )

Set Union{ Member, Member, Member, }

{ Tuple, Tuple, Tuple, }

Member


15/37

Cube Basics - Dimensions

Cubes SQL Equivalent

Dimension Table

Attribute Column

Member Row

Dimension A denormalised business entity

Customer / Product / Date / Employee / etc.

Sourced from a SQL Server table in the data warehouse


16/37

Cube Basics - Members

Member

A single item from a dimension attribute

e.g. a Date, a Year, a product, an employee

Set

Multiple members OF THE SAME attribute

e.g. Today & Yesterday

or Customer IDs 123, 2921 and 5234


17/37

Cube Basics - Members


18/37

Syntax - Members

[Dimension].[Attribute].[Member]

[Date].[Year].[2013]

[Date].[Date].[2013-02-20]

[Customer].[Customer].[Waitrose]

[Customer].[Country].[UK]

[Date].[Year].CURRENTMEMBER


19/37

Syntax Member Keys

[Dimension].[Attribute].&[Member]

[Date].[Year].[2013] (Name)

[Date].[Year].&[2013] (Key)

[Date].[Month].[March] (Name)

[Date].[Month].&[3] (Key)


20/37

Cube Basics - Sets


21/37

Syntax - Sets

{ MEMBER1, MEMBER2, MEMBER3 }

{ [Date].[Year].[2010], [Date].[Year].[2012] }

{ [Date].[Year].[2010] : [Date].[Year].[2012] }

{ null : [Date].[Year].CURRENTMEMBER }


22/37

Cube Basics - Tuples


23/37

Syntax - Tuples

( MEMBER, MEMBER, )

([Date].[Year].[2012],

[Customer].[Customer].[Waitrose])

([Date].[Year].[2012],

[Customer].[Customer].[Waitrose],[Product].[Product].[Banana])


24/37

Cube Basics Tuples revisited!


25/37

Cube Basics Tuples revisited!


26/37

Cube Basics Sets revisited!


27/37

Syntax - Sets

{ MEMBER1, MEMBER2, }

{ (TUPLE1), (TUPLE2), }

{ ([Date].[Year].[2010], [Product].[Product].[Banana])

, ( [Date].[Year].[2012], [Product].[Product].[Apple] ) }


28/37

Demo

Basic Queries

SELECT xxx ON COLUMNS

SELECT xxx ON ROWS

MEMBERS

TUPLES

SETS

Basic Calculations


29/37

Dimension Navigation

CURRENTMEMBER

The query has context

The current member relevant in the query

[Date].[Year].CURRENTMEMBER

PREVMEMBER

The one before to the current member [Date].[Year].PREVMEMBER


30/37

Relative Calculations

Change since previous year

[Date].[Year].CURRENTMEMBER- [Date].[Year].PREVMEMBER


31/37

Hierarchies

Year

Month

Date

Product Type

Product Group

Product

Product Version


32/37

Parent Child Hierarchies

Top Dog

Manager

Employee

Employee

Employee

Employee

Employee


33/37


DESCENDANTS

ANCESTORS

PARENT

CHILDREN

SIBLINGS


34/37

Demo Dimension Navigation


DESCENDANTS

ANCESTORS

PARENT

CHILDREN

SIBLINGS


35/37

Visualising Queries

Very different to SQL

Think in blocks

E.g. All data EXCEPT for xxx

Run two queries and subtract them

minus


36/37

Think in MDX, not SQL

Get your head around the lingo

Member, Set, Tuple

Dimension / Measuregroup

Keep it simple

Use MDX for what its good for

MDX 101 - Summary


37/37

MDX 101 Questions?.....

www.MDXpert.com

MDX Studio

www.PurpleFrogSystems.com [email protected]

www.PurpleFrogSystems.com/blog @PurpleFrogSys
http://www.mdxpert.com/http://www.purplefrogsystems.com/http://www.purplefrogsystems.com/bloghttp://www.purplefrogsystems.com/bloghttp://www.purplefrogsystems.com/http://www.mdxpert.com/

sql sat cambridge - mdx 101 - 20130928

Documents