更新不同表相同字段不同值

UPDATE SA.SUBMIT SA
   SET SEND_STATE = (SELECT SEND_STATE
                       FROM PHS.SUBMIT
                      WHERE PHS.SUBMIT.ID = SA.ID
                        AND SUBSTR(SA.SEND_STATE, 15, 1) <>
                            AN.SUBMIT.SEND_STATE
                        AND SUBSTR(SA.SEND_STATE, 15, 1) IS NOT NULL)
 WHERE SA.ISCHGSTATUS = 0 AND EXISTS
 (SELECT 1
          FROM PHS.SUBMIT PHS
         WHERE PHS.ID = SA.ID
           AND SUBSTR(SA.SEND_STATE, 15, 1) <> PHS.SEND_STATE
           AND SUBSTR(SA.SEND_STATE, 15, 1) IS NOT NULL)

SQL說明：更新sa用戶的submit表，與an用戶的submit表相同字段但值不相同的數據。