be used. For example, this is an untrustworthy way of trying to
avoid division by zero in a WHERE clause:
-SELECT ... WHERE x <> 0 AND y/x > 1.5;
+SELECT ... WHERE x <> 0 AND y/x > 1.5;
but this is safe:
-SELECT ... WHERE CASE WHEN x <> 0 THEN y/x > 1.5 ELSE false END;
+SELECT ... WHERE CASE WHEN x <> 0 THEN y/x > 1.5 ELSE false END;
A CASE construct used in this fashion will defeat optimization attempts,
so it should only be done when necessary.