This morning FINDSTRING([Description 01],"COST POOL", 1)==1? "Yes": "No" parsed. So back to the original problem.

I need one level of nesting to handle second condition. Following SQLChik's tutorial...

Field == "TrueCondition1" ? “True” : ( Field == "TrueCondition2" ? “True” : ( Field == "TrueCondition3 " ? “True” : ( Field == "TrueCondition4" ? “True” : “False" ) ) )

I note there are many TRUEs and one FALSE if all hopes are dashed, so I do this:

FINDSTRING([Description 01],"COST POOL", 1)==1? SUBSTRING(TRIM([Business Unit]), 1,3)=="MFM"?:(SUBSTRING(TRIM([Business Unit]), 4,50)): NULL

Translated: see if the string "Cost Pool" exists in [Description 01] column, if it does, see if first 3 letters of [Business Unit] are "MFM", if yes, retain the letters after MFM. But, if "Cost Pool" doesn't exist, put NULL in column.

This expression doesn't parse. Is it because I am missing parentheses?