SELECT "l".A "A", "l".B "B", (CASE
WHEN "l".C THEN 2
ELSE 1
END) "X", (CASE
WHEN "l".D THEN 2
END) "Y", (CASE
WHEN "l".E THEN 2
END) "Z"
FROM T1 "l"
correct syntax is: WHEN "l".C = 1 THEN 2