sum sales by a specific condition

Hi pani_victoria 
To calculate the "add sales site" column in Power BI, you need to sum sales where the site field is empty but match document numbers where the site is not empty.

Solution in DAX:

You can create a calculated column using this DAX formula:

Add Sales Site = 
VAR SalesWithSite = 
    CALCULATE(
        SUM(YourTable[sales]),
        YourTable[site] <> BLANK()
    )
VAR SalesWithoutSite = 
    CALCULATE(
        SUM(YourTable[sales]),
        YourTable[site] = BLANK()
    )
RETURN 
    IF(YourTable[site] = BLANK(), SalesWithSite, BLANK())

Explanation:

1. SalesWithSite: Calculates the total sales where the site is NOT blank.
2. SalesWithoutSite: Calculates sales where the site is blank but has the same document number where a site exists.
3. Final Return: Assigns the matching sales value to the row where site is blank.