value = BLANK() versus ISBLANK(value)

[lbendlin]

This is a followup from https://community.powerbi.com/t5/DAX-Commands-and-Tips/seaching-for-keywords-in-text-for-use-as-inde...

Why does this work?

but this doesnt?

[lbendlin · Accepted solution]

Mystery solved. CONCATENATEX never returns blank. At the minimum it returns an empty string.  So there seems to be a bug in DAX that allows the comparison of an empty string to BLANK() to be true.

[lbendlin]

@marcorusso  I ran this in DAX studio.  Is there a good explanation for this?

evaluate row(
"Test1",ISBLANK(""),
"Test2",""=BLANK()
)

[marcorusso]

Here: https://www.sqlbi.com/articles/blank-handling-in-dax/

[lbendlin]

Thank you Marco.  Would be nice if the article could also mention the "=="  operator.

[marcorusso]

Good suggestion, I just added an example of == in that article. Thanks!

[harshnathani]

Hi @lbendlin ,

https://www.youtube.com/watch?v=C26DQkb4hyY

Have a look at this video. 

Regards,

Harsh Nathani

[lbendlin]

@harshnathani  Thank you. I am not ashamed to admit that I was not aware of the equality operator ("==") being available in DAX.  That makes more sense now.  Single equal sign does a type transformation.  Thanks again!