Introduction to Data Analysis Expressions (DAX)

Alan KooPresident & Founder | Puerto Rico PASS

Senior Consultant | Nagnoi, Inc.

Analysis Services 2012 Flavors

• Personal BI: PowerPivot for Excel 2010• Team BI: PowerPivot for Sharepoint• Corporate BI (SSDT):–Analysis Services 2012 Tabular–Analysis Services 2012 Multidimensional

Tasting the Flavors of SSAS 2012 | SQL Saturday Puerto Rico | Alan Koo | www.alankoo.com

What is DAX

• Programming language of SSAS 2012 Tabular and PowerPivot

• Simple, clean, powerful, fast, not easy• Tabular requires simpler data modeling for good

result• Thinking in DAX is a new attitude

BI Semantic Model: The Analysis Services 2012 Foundation

From Personal to Corporate BI

Tasting the Flavors of SSAS 2012 | SQL Saturday Puerto Rico | Alan Koo | www.alankoo.com

DAX MDX

Sample Data - Contoso

A quick refresh

Building Models in PowerPivot

& Analysis Services Tabular Mode

Data Analysis Expressions (DAX)

Calculated Columns and Measures

• Calculated Columns– Columns in the database, calculated with DAX– Stored in the database

• Measures– DAX formulas computed on aggregates of values– Computed at query time

• Different usages for different modeling needs

Calculated Columns

• Formula is evaluated for each row• Results are stored back into PowerPivot as any

other column• Columns can be used for both slicing data and

summarizing values• Part of the model, available for use in any

PivotTable • Usable by other AS clients in PowerPivot for

SharePoint

DAX includes 80 Functions from Excel

12

Date and Time Information Math and Trig Statistical TextDATE ISBLANK ABS AVERAGE CONCATENATEDATEVALUE ISERROR CEILING, ISO.CEILING AVERAGEA EXACTDAY ISLOGICAL EXP COUNT FINDEDATE ISNONTEXT FACT COUNTA FIXEDEOMONTH ISNUMBER FLOOR COUNTBLANK LEFTHOUR ISTEXT INT MAX LENMINUTE LN MAXA LOWERMONTH Logical LOG MIN MIDNOW AND LOG10 MINA REPLACESECOND IF MOD REPTTIME IFERROR MROUND RIGHTTIMEVALUE NOT PI SEARCHTODAY OR POWER SUBSTITUTEWEEKDAY FALSE QUOTIENT TRIMWEEKNUM TRUE RAND UPPERYEAR RANDBETWEEN VALUEYEARFRAC ROUND

ROUNDDOWNROUNDUPSIGNSQRTSUMSUMSQTRUNC

Calculated Measures

• Evaluated dynamically per value in PivotTable

• Part of the model, available to other PivotTables

• Usable by any AS client through PowerPivot for SharePoint

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DAX Aggregation Functions

• SUM, AVERAGE, MIN, MAX, COUNT take column references

• Extensions aggregate an expression over the rows of a table

• SUMX (Table, Expression)

• AVERAGEX (Table, Expression)

• COUNTAX (Table, Expression)

• MINX (Table, Expression)

• MAXX (Table, Expression)

• COUNTROWS (Table)14

DAX Demo

Calculated Columns and

Measures (Functions)

Beyond Excel

You Are Here

DAX in Action!

Time Intelligence

Useful Resources

• Data Analysis Expressions (DAX) Overview – MSDN http://msdn.microsoft.com/en-us/library/gg399181.aspx

• DAX in Action! – Alberto Ferrari in Project BotticelliProjectBotticelli.com

• SQLBI.com Articleshttp://www.sqlbi.com/articles/all/

• Microsoft Business Intelligence y más… - Alan Kooalankoo.com

Calculated Columns

• Calculated columns– Stored in the database, computed at process time– On big fact tables can consume a lot of RAM– Required to slice data

• Measures– Computed at query time, do not use RAM

• Prefer measures, whenever possible

Summary

• DAX is fast: its speed of DAX makes simpler modeling techniques shine

• Tabular requires thinking in DAX, less modeling, more complex expressions

• PowerPivot is a great prototyping tool, models created in Excel can be deployed on SSAS Tabular

Credits for this Session

• Ashvini Sharma – Microsoft Corporation• Alberto Ferrari and Marco Russo - SQLBI

Questions?

Nestor Figueroa | 787.671.8244powerpivotworkshop@nagnoi.com

Authorized Training Center

Designed for professionals who want to use PowerPivot’s full capabilities, the PowerPivot Workshop is a two/three-day course that covers PowerPivot topics,

starting from basic concepts and moving on up to complex data models and DAX formulas with the goal

to facilitate the use of PowerPivot in the real world.

Puerto Rico PASS ChapterLike us in Facebook! Our next meet is on Nov 29th.

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