Handling null when adding columns from table with no results

Hi KNP,

you have 2 options: you integrate a test for null into you function or you do that after calling it. The later looks like:

= Table.AddColumn(
     LastStep, 
     "NewColumnName", 
     each
          let
               functionResult = myFunction(_, another param, another param),
          in
               if functionResult = null then 0 else functionResult
    ) 

The important thing is that you call your custom function only once and save the result into a variable.

A proof: The first query runs for 5 seconds, the other for 10 seconds.

/*
let
    Source = Function.InvokeAfter(() => 5, #duration(0, 0, 0, 5)),
    Result = if Source = null then 0 else Source
in
    Result
*/

let
    Result = if Function.InvokeAfter(() => 5, #duration(0, 0, 0, 5)) = null then 0 else Function.InvokeAfter(() => 5, #duration(0, 0, 0, 5))
in
    Result