How to add a blank cell when formula returns error or null in Power Query

[mdrammeh]

Hello,

I have two calculated columns with different expressions in Power Query. I want to calculate the difference between the two columns and return a blank value where the formula returns an error message. 

The first column (% Change) is calculated by the difference of =  (Projected $ - Cost)/Projected

The second column used the result of the first column and subtracted it from 1. i.e. % Complete = 1-(% Change) value. 

This way when the result is displayed on my power PowerPivot table, the value in the cell remains blank instead of "NA#".Also, if there is a better way to do this calculation, please share your thoughts as well.

Thanks!

[Datatouille]

Hi @mdrammeh

I think you should not use Power Query but Dax language to perform this kind of calculations.

And because it involves ratios, you should create DAX measures rather than calculated columns - otherwise you'll get wrong figures when analysing your percentages.

Why ? Because a/b + c/d + e/ f is NOT equal to (a + c + e) / (b+d+f)

You should always do "the ratios of the sum rather than the sum of the ratios" (Kimball).

So create these 2 measures:

[Pct Change] = 1 - Sum(Table[Cost]) / Sum (Table[Projected])

[Pct Complete] = 1 - [Pct Change]

Format them as % and use them in any graphs. These measures will automaticcaly adjust to filter context.

Your Pct calculations will be both correct and dynamic.

[mdrammeh]

So are you suggesting I use DAX functions in Excel or Power BI instead of Power Query? Could you share an example from the Query editor? 

[Datatouille · Accepted solution]

Yes, I do suggest you use DAX measures in Power BI Desktop  (or Excel if you are using Excel with powerpivot).