What does question marks after a fieldname mean ex: "record[field]?"

[PBIDevNoob]

I've been trying to learn the the TripPin example by Microsoft and I noticed that there were times when they were adding question marks (?) after the fieldname. Is there any point to this? I've tried removing it, and it didn't seem to make any difference. 

[ImkeF · Accepted solution]

Hi @PBIDevNoob ,

This prevents an error being risen if the field isn't included in your table. 

Instead a null will be returned for the missing column(s).

[ImkeF · Accepted solution]

Hi @PBIDevNoob ,

This prevents an error being risen if the field isn't included in your table. 

Instead a null will be returned for the missing column(s).

[PBIDevNoob]

Oh. That's nifty. Does Ms have any documentation on this? I've been looking everywhere online.

[ImkeF · Accepted solution]

Its in the language specs: https://docs.microsoft.com/en-us/powerquery-m/power-query-m-language-specification

[PBIDevNoob]

You're a life saver. Thanks!