what I want is:

if pk exists in both Table A and B, ignor record in Table B

if pk exist either in Table A or B, return it

think should union 3:

SELECT A.PK AS A_PK, A.Value AS A_Value FROM Table_A A INNER JOIN Table_B B ON A.PK = B.PK
UNION
SELECT A.PK AS A_PK, A.Value AS A_Value FROM Table_A A LEFT JOIN Table_B B ON A.PK = B.PK WHERE B.PK IS NULL
UNION
SELECT B.Value AS B_Value, B.PK AS B_PK FROM Table_A A RIGHT JOIN Table_B B ON A.PK = B.PK WHERE A.PK IS NULL

hope it works

所有跟帖： 

• 开始又不说清楚，哎 -令狐冲冲- ♀ (0 bytes) () 03/05/2013 postreply 20:09:15

• 墨索里尼总是有理，过去有理，现在有理，而且将来永远有理 -奉旨灌水- ♀ (87 bytes) () 03/05/2013 postreply 20:13:21

• 这啥呀？ -令狐冲冲- ♀ (0 bytes) () 03/05/2013 postreply 20:14:47

• 这句名言出自一部阿尔巴尼亚的电影，电影的名子是《宁死不屈》。 -奉旨灌水- ♀ (320 bytes) () 03/05/2013 postreply 20:19:59

• 估计你的父母都不一定看过，嘿嘿 -奉旨灌水- ♀ (4 bytes) () 03/05/2013 postreply 20:21:09

• 直接用not exists 不就行了？搞的这么复杂 -令狐冲冲- ♀ (0 bytes) () 03/05/2013 postreply 20:13:46

• how to deal exist? 不搞的这么复杂 -奉旨灌水- ♀ (90 bytes) () 03/05/2013 postreply 20:15:54

• 回复：how to deal exist? 不搞的这么复杂 -令狐冲冲- ♀ (230 bytes) () 03/05/2013 postreply 20:21:46

• OK, I'll try. Thanks, vielen dank.Merci, תוד&# -奉旨灌水- ♀ (0 bytes) () 03/05/2013 postreply 20:25:40