ＤＢ2での条件分岐

SELECT
id,
pass,
CASE WHEN end_flag = '1' THEN 'login_error01'
WHEN login_page = '1' THEN 'form1-mnu'
WHEN login_page = '2' THEN 'form2-mnu'
WHEN login_page = '3' THEN 'form3-mnu'
WHEN login_page = '4' THEN 'form4-mnu'
END AS LOGINPAGE
FROM
login
WHERE
id = '" + req_id +"' AND
pass = '" + req_pass + "'";