[ORACLE]OUTER JOIN

SELECT count(*)
FROM   EMAIL_GRP A
LEFT OUTER JOIN EMAIL_TARGET B
ON A.MAIL_GRP_NO = B.MAIL_GRP_NO
WHERE  B.SEND_YN = 'N'
AND   A.SEND_TYPE_CD='S'

UPDATE EMAIL_TARGET B
SET B.SEND_YN = 'Y'
WHERE EXISTS (SELECT MAIL_GRP_NO FROM EMAIL_GRP A WHERE A.MAIL_GRP_NO = B.MAIL_GRP_NO AND A.SEND_TYPE_CD = 'S' AND B.SEND_YN = 'N')