Expressions that yield variant data-type error message in if statement

[kasiaw29]

Hi community, 

I'm tryingto create a custom column that checks some dates and returns "LATE" if it meets criteria or a date otherwise. 

My formula goes as follows:

Actual Start =

IF(ISBLANK(RELATED('Sub Project w Activities'[Actual Start]))
&& 'Activity History'[Latest Customer Agreed Dispatch Date]<=TODAY(),"LATE",RELATED('Sub Project w Activities'[Actual Start]))

In simple terms, if actual start is blank and latest customer agreed dispatch date is before today then it's late (refers to activity), if however actual start is there I just want to show it. I've looked through form and previous issues indicate using FORMAT but I don't see where to use it, all my dates? 

[amitchandak · Accepted solution]

@kasiaw29 , One place you are returning "Late" another place date. Power BI dax Do not allow different data types

Try like

Actual Start =

IF(ISBLANK(RELATED('Sub Project w Activities'[Actual Start]))
&& 'Activity History'[Latest Customer Agreed Dispatch Date]<=TODAY(),"LATE",RELATED('Sub Project w Activities'[Actual Start])&"")

[kasiaw29]

Thanks @amitchandak I've also placed FORMAT in my resultiffalse 

IF(ISBLANK(RELATED('Sub Project w Activities'[Actual Start])) && 'Activity History'[Latest Customer Agreed Dispatch Date]<=TODAY(),"LATE",FORMAT(RELATED('Sub Project w Activities'[Actual Start]),""))

Which simingly does the same thing. Thank you so much for your fast reply!