SO COUNT DAX MEASURE

[GermanTersoglio]

Hello everyone!
I am having the following situation:
I have a FACT table called "SalesLines" which is connected to DIM "Invoiceheader"

SalesLines has multiple lines per Sales Order
InvoiceHeader as a DIM has just one Sales Order per line.

I need a dax measure to know the count of Sales Orders. 
If i do it over the FACT, I get a huge number because when a Sales Order has 4 lines is counting as 4. If I do it over the DIM table, the visual has low performance and takes 2 min to display.

The closest that i have been is here:

- VAR Factkey = MAX(InvoiceLines[InvoiceKey])

return

 COUNTX( FILTER(SalesLines, RELATED('Invoice Header'[InvoiceKey]) = Factkey),RELATED('Invoice Header'[SalesId]))

 
But I get the grand total as 1 and not the sum. 

Also i have tried simpler things like:
-  COUNTX(SalesLines, RELATED('Invoice Header'[SalesId]))

But this returns the count of each line obiously 

Any help is appreciated 

[tamerj1 · Accepted solution]

Hi @GermanTersoglio 
If the column exists in the fact table the

= DISTINCTCOUNT ( 'SalesLines'[SalesId] )

If not then

=
COUNTROWS (
    DISTINCT (
        SELECTCOLUMNS (
            SalesLines,
            "@SalesID", RELATED ( 'Invoice Header'[SalesId] )
        )
    )
)

[GermanTersoglio]

Hi Tamerj,
I was facing my measure in the wrong way. 
You solution works perfectly. I really appreciate your help.

Thanks for sharing your knowledge 🙂

[FreemanZ]

hi @GermanTersoglio 

Seems you are plotting with InvoiceLines[InvoiceKey] and the two tables are joined on this column, try like

measure =

COUNTROWS(RELATEDTABLE(SalesLines))

Or tell us more about your case.