What is the key difference between FIRSTNONBLANK and FIRSTNONBLANKVALUE ?

Hi ddpl ,

FIRSTNONBLANKVALUE() returns the first non-blank value of <expression> corresponding to the sorted values of <column>.

FIRSTNONBLANKVALUE(<column>, <expression>)

This function is different from FIRSTNONBLANK in that the <column> is added to the filter context for the evaluation of <expression>. It is equivalent to :

=
CALCULATE (
    <Expression>,
    FIRSTNONBLANK ( <Column Name>, CALCULATE (<Expression> ) )
)

I have built a simlply data sample for you to understand:

Measure 1 = FIRSTNONBLANK('Table'[Type],CALCULATE(SUM('Table'[Value])))

Measure 2 = FIRSTNONBLANKVALUE('Table'[Type],CALCULATE(SUM('Table'[Value])))

Measure 3 = FIRSTNONBLANKVALUE('Table'[Type],SUM('Table'[Value]))

• Measure 1 returns the first Type in the list whose Value are not empty, Since Type is Text ,it will in alphabetical order ,is "B"
• Measure 2 returns the Value corresponding to the first Type whose Value is not empty, that is, the Value of "B"= the result of the Measure 1 , is 2
• Measure 3 is the same as Measure 2

Refer to:

FIRSTNONBLANKVALUE function (DAX) - DAX | Microsoft Docs

Best Regards,
Eyelyn Qin
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