I haven't figured out why, but found that I had to use:
WHERE courseID IN (" & $courses & ")";
"" ; "" )
in previous cases when I wanted to get the In operator to work from such a comma separated list.
Thanx a lot,
I guess when you insert the list as "text" into the query the SQL engine doenst even know you are using a variable
Correct. Back when using MS Access, this was a common way to "calculate" an SQL query and also works in FileMaker. I have a custom function that I put into the string expression like this. It inserts table and field references into the calculation in such manner that renaming a table, table occurrence or field does not break the query expression. It's ugly, but it protects my work form such changes.