Leading underscores are a known problem with ExecuteSQL.
Try this mod:
ExecuteSQL ( "SELECT Material_Name FROM Material_Reading WHERE \"_Room_KF\" = 4089"; "";"")
That was it! Thanks!
I have gotten in the habit of using the escaped quotes on all the field and table names.
While not necessary for all names, it may help to escape+quote. Just remember that SQL uses the dot between so each part is escape-quoted:
This is NOT correct:
-- sent from myPhone --