You can't use ="" to find records where the field is empty.
\"fk_lineItemID\" Is NULL
Yes that fixed it thank you.
I believe I have found a bug in the Filemaker 13 behavior. When using the ? placeholder in an ExecuteSQL statement filemaker applies the usual calculation engine error correction. This converts "" into Null. I read an excellent article on this somewhere that I can not find at the moment. Modifying my original calculation to remove the AND statement works as expected. Am I missing something
WHERE \"fk_lineItemID\" = ?";
""; ""; "")
works as expected
In that case, this should be reported in Report an Issue as a bug.