Implementing Common Business Calculations in DAX - Chris Webb

8/9/2019 Implementing Common Business Calculations in DAX - Chris Webb

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Implementing Common

Business Calculations in DAXChris Webb

[email protected] www.crossjoin.co.uk

mailto:[email protected]:[email protected]


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DAX Calculations

Who am I?• Chris Webb ( [email protected] )• In epen ent consultant specialising in

Anal!sis "er#ices an $DX (an %o&er%i#ot

an DAX') http &&&.crossjoin.co.uk• Blogger http c&ebbbi.spaces.li#e.com • Author

–

$DX "olutions *n

+ ition – +,pert Cube De#elopment With Anal!sis"er#ices *--

mailto:[email protected]://www.crossjoin.co.uk/http://cwebbbi.spaces.live.com/http://cwebbbi.spaces.live.com/http://www.crossjoin.co.uk/mailto:[email protected]


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DAX Calculations

Agen a• What is DAX an &h! shoul I learn

it?• Calculate columns an calculate

measures• /o& conte,t an 0lter conte,t•

Calculate()• 1alues()• Demos2 emos2 emos'


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DAX Calculations

What is DAX?• DAX is the ne& calculation language 3or

%o&er%i#ot• $DX is still the 4uer! language

• It is a multi imensional calculation languagelike $DX2 but the esign goals &ere• $ake it eas! to o common calculations (easier

than $DX)•

$ake it eas! to use 3or +,cel po&er users2 hencethe +,cel5base s!nta,• DAX e,pressions are limite to a single

(though o3ten #er! long) line o3 co e


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DAX Calculations

Wh! learn DAX?• 6our po&er users &ill be learning it2 an !ou7ll nee to

un erstan &hat7s going on in their %o&er%i#otmo els

• It7s #er! likel! that it &ill be use in 3uture #ersions o3""A" 8 possibl! as an alternati#e to $DX 3or somecalculations

• We love both DAX and MDX, and MDX is not going away. Thechallenge for us is to bring them together. We have some

promising directions. That said – thin! you"ll see DAX evolving in

new important directions that MDX will never cover, and a largeand growing portion of the calc wor! will be done in DAX. #o myadvice stands$ all you guys need to become DAX gurus

ASAP .Amir Netz, Microsoft


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DAX Calculations

DAX "!nta, an 9unctions• DAX s!nta, is base on +,cel s!nta,

• :nl! thing to &atch out 3or is !ou nee to use ;; an I 3or e iting DAX is terrible 8 can use

=ote%a an Colin Ban0el 7s DAX languagetemplate instea


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/e3erencing Columns an $easures

• DAX usuall! re4uires 3ull! 4uali0enames2 eg• $! able $!Column• $! able $!$easure

• 6ou can use un4uali0e names incalculate column e0nitions2 &henre3erring to other columns in thesame table

• DAX cannot use stan ar +,cel cellre3erences to ata else&here in the



Calculate Columns• DAX can be use to create t&o t!pes o3

calculation calculate columns an calculatemeasures

• Calculate columns are eri#e columns in a%o&er%i#ot table• Are e0ne insi e the %o&er%i#ot >I• A3ter the! are create 2 the! beha#e like an! other

column• heir #alues are calculate imme iatel! a3ter the real

ata has been loa e into %o&er%i#ot• Can be use to o basic + &ork2 eg concatenating

0rst an last names2 eri#ing !ears 3rom ates etc



Calculate $easures• Calculate measures pro#i e the numeric

#alues !ou see aggregate in pi#ot tables• All measures are calculate measures in

%o&er%i#ot'• Are e0ne &ithin the pi#ot table in +,cel• Are calculate at 4uer! time

• Basic sum2 count2 min2 ma, an a#eragecalculate measures can be create 3rom theright5click menu

• $ore a #ance calculate measures can becreate b! entering !our o&n DAX e,pression



/o& Conte,t an 9ilterConte,t

• /o& conte,t re3ers to the current ro& &here acalculation is taking place• here is no ro& conte,t &ithout a DAX aggregation 3unction

• 9ilter conte,t re3ers to the currentl! selecte item oneach column on each table• 1er! similar to the Current$ember 3unction in $DX2 but

han les multiselect elegantl!• 9ilter conte,t 3ollo&s the one5to5man! relationships

bet&een tables• Both ro& an 0lter conte,t must be taken into

account &hen &riting e,pressions 3or calculatemeasures


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/o& Conte,t &ithCalculation



Calculate()• he Calculate() 3unction is the ke! to all

a #ance DAX calculation 3unctionalit!• "ignature Calculate(+,pression2 "et9ilterE2

"et9ilter*2...)• It allo&s an! e,pression to be e#aluate in aspeci0c 0lter conte,t

• It &orks as 3ollo&s•

$o i0es the current 0lter conte,t accor ing to the"et9ilter arguments !ou pass in• "hi3ts the ro& conte,t onto the 0lter conte,t• +#aluates !our e,pression in the ne& 0lter conte,t



Calculate()• "et9ilter arguments can either be

• Boolean e,pressions2 egCA C> A +(C:>= /:W"()2 Consultants "kill FG$DXG)

• able 3unctions2 so the 0lter conte,t 3or an! table isset to the ro&s returne b! the table 3unction2 egCA C> A +(C:>= /:W"()2 9I +/(Consultants2Consultants $easureE H ))

• >se3ul table 3unctions inclu e•

1alues()2 &hich returns a list o3 istinct #alues in acolumn in the current 0lter conte,t• All()2 &hich returns a list o3 all the #alues in a column

ignoring 0lter conte,t


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DAX Calculations

/atio to All an /atio to%arent

• A common e,ample o3 a Jratio to all7 an Jratio to parent7calculations is a market shares

• he numerator 3or this kin o3 calculation is eas!">$(KConsultantsK $easureE )

• he enominator is the Jall7 or Jparent7 total• o get the total #alue o3 a measure &ith all 0lter conte,t

cleare &e nee to use All( able)2 egCA C> A +(">$(KConsultantsK $easureE )2A (Consultants))

• o get the total #alue o3 a measure &ith 0lter conte,t 3or just one column remo#e 2 &e nee All(Column)2 egCA C> A +(">$(KConsultantsK $easureE )2A (Consultants Consultant ))


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DAX Calculations

%re#ious 6ear Lro&th• he 3ollo&ing is the best approach• FCA C> A +(">$(9actInternet"ales "alesAmount )

2 DA +ADD(DimDate 9ullDateAlternate e! 2 5E2 6+A/)2 A (DimDate))

• Works b!• 9in ing all the ates in the current !ear• "hi3ting each ate back one !ear• "etting this as the 0lter conte,t•

"umming "alesAmount 3or these ates• B> &ill onl! gi#e correct results i3 !ou ha#e a

complete set o3 ates in !our !ear'


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DAX Calculations

%re#ious 6ear Lro&th• Al&a!s a goo i ea in DAX to break comple,

calculations up into a series o3 simpler calculatemeasures

• "o2 i3 &e use the pre#ious 3ormula to e0ne acalculate measure calle %re#ious 6ear "ales2 thegro&th calculation becomes

• FI9(9actInternet"ales %re#ious 6ear "ales F-2 B A= ()

• 2(">$(9actInternet"ales "alesAmount ) 59actInternet"ales %re#ious 6ear "ales ) 9actInternet"ales %re#ious 6ear "ales )

• =otice2 like in $DX2 &e nee to trap i#ision b! Mero


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DAX Calculations

/ules 3or ime Intelligence 3unctions

• 9i#e rules 3or using ime Intelligence 3unctionsE. =e#er use the atetime column 3rom the 3act table in

time 3unctions.*. Al&a!s create a separate ime table2 an make sure

it contains complete !ears. Create relationships bet&een 3act tables an the

ime table.N. $ake sure that relationships are base on a atetime

column (an =: base on another arti0cial ke!column).O. he atetime column in the ime table shoul be at

a! granularit! (&ithout 3ractions o3 a a!).


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DAX Calculations

I3 !ou on7t 3ollo& therules...

• As &e7#e alrea ! seen2 not ha#ing complete!ears makes it har to o relati#e timecalculations

•In m! e,ample2 since I joine on a surrogateke! an not a Date ime ke!2 I nee e to aAll(DimDate) to m! calculation

• 6ou can7t use /+ A +D() to bring the ate

o&n to the 3act table either2 because thiscauses a circular re3erence error'• =ee to either alter the un erl!ing relational table

or #ie&2 or import the ate imension table t&ice


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DAX Calculations

6ear to Date• uckil! there are man! built5in time

intelligence 3unctions 3or common calculations• +g 3or oing !ear5to5 ate sums2 &e ha#e

otal6 D• F : A 6 D(">$(9actInternet"ales "alesAmount )2DimDate 9ullDateAlternate e!

2 A (DimDate))• In this case2 otal6 D is a #ariant o3 Calculate&ith some 0lters set automaticall!


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DAX Calculations

otal to Date• A total5to5 ate gets the running total 3rom

the 0rst ate &e ha#e in our ata• =o built5in 3unction 3or it

• We nee to use Calculate an set the 0lterto all ates 3rom the 0rst e#er ate to thelast ate in the current conte,t• We can use DA +"B+ W++= to get this ate

range• he 0rst ate can be got b! using B A= ()• he last ate &ith the A" DA +() 3unction


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DAX Calculations

otal to Date• he 0nal #ersion is

FCA C> A +( ">$(9actInternet"ales "alesAmount )

2DA +"B+ W++=(KDimDateK 9ullDateAlternate e!

2 B A= ()2A" DA +( KDimDateK 9ullDateAlternate e! ))2 All(KDimDateK))


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DAX Calculations

1alues() 8 like Current$ember butbetter'

• he 1alues() 3unction acts like the $DXCurrent$ember 3unction

• But it is better 1alues() returns a table2 so ithan les multiselect• Although &hen the table it returns onl! contains one

ro& &e can still o a irect comparison &ith another#alue

• he Distinct() 3unction &orks e,actl! the same

&a! as 1alues() but• 1alues() &ill return the >nkno&n $ember• Distinct() &ill not


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DAX Calculations

Distinct Count• o 0n a istinct count2 &e nee to

count the ro&s in a table containingonl! the istinct #alues 3rom acolumn

• he 1alues() 3unction returns such atable

• Because it7s a table2 all &e nee too is count the number o3 ro&s in it

• FC:>= /:W"(1A >+"(Consultants"kill ))


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DAX Calculations

9inal houghts• DAX oes the eas! stuP #er! easil!• DAX oes the me ium5har stuP &ell too

• =ot sure i3 po&er users &ill get it2 but• It7s easier than $DX• It7s more "Q 5like2 so more e#elopers &ill get it• It7s more elegant than $DX in man! &a!s2 eg

multiselect• DAX oes not o the reall! har stuP &ell at all

• "o 3or 0nancial apps2 3or e,ample2 $DX still &ins• But 3or ho& long?

• I like DAX a lot


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DAX Calculations

inks• http blogs.ms n.com po&erpi#ot• http &&&.po&erpi#ot.com• http po&erpi#otgeek.com•

http po&erpi#ott&ins.com• http po&erpi#otpro.com• http &&&.po&erpi#ot5in3o.com• http c&ebbbi.spaces.li#e.com• http social.ms n.microso3t.com 9orums en5>"

s4lkjpo&erpi#ot3ore,cel threa s• http &&&.business5intelligence.k ejonge.net

• http s4lblog.com blogs marcoRrusso


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hanks'


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Implementing Common Business Calculations in DAX - Chris Webb

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