Variable Help

[RZAU]

Hi Power BI experts

I am still learning Power BI. And I am confused about this variable concepts.  Could you pls help explain a little bit?  Thank you!

Example:

Sales[Order Position]=
1 VAR CurrentOrderNumber= Sales[Order Number]

2 Var Postion=
    Calculate (

               DISTINCTCOUNT(Sales[Order Number]),

               Sales[Order Number]<=CurrentOrderNumber  //My confusion is here.  Is this the same column?  Both refer to same Sales[OrderNumber] since CurrentOrderNumber=Sales[Order Number]? //
)
Return  Position

[FreemanZ · Accepted solution]

once defined, the variable is stored as constant value.  so in expression like:

Sales[Order Number]<=CurrentOrderNumber

the left part is a real variable row by row, the right part is actually a constant defined before. 

[v-binbinyu-msft · Accepted solution]

Hi @RZAU ,

For understand VAR statement, you should understand the context concept in Power BI, because it is influence by context.

VAR: Stores the result of an expression as a named variable, which can then be passed as an argument to other measure expressions. Once resultant values have been calculated for a variable expression, those values do not change, even if the variable is referenced in another expression.

Please refer below notes for your dax formula:

Sales[Order Position] =
VAR CurrentOrderNumber = Sales[Order Number] //get current value for [Order Number] column according to the line context
VAR Postion =
    CALCULATE (
        DISTINCTCOUNT ( Sales[Order Number] ),
        Sales[Order Number] <= CurrentOrderNumber //use the CurrentOrderNumber to filter the [Order Number]column, now CurrentOrderNumber is just a value not a column
    )
RETURN
    Position

 For more details, you can read related document: VAR keyword (DAX) - DAX | Microsoft Learn , Variables in DAX - SQLBI

Best regards,
Community Support Team_Binbin Yu
If this post helps, then please consider Accept it as the solution to help the other members find it more quickly.

[FreemanZ · Accepted solution]

once defined, the variable is stored as constant value.  so in expression like:

Sales[Order Number]<=CurrentOrderNumber

the left part is a real variable row by row, the right part is actually a constant defined before.