如何在sql語句?我想要做這樣的事情:SQL如果語句
SELECT DISTINCT exchange.id userid, exchange.name username, exchange.lastactivity lastactivity, exchange.id avatar, exchange.id link, cometchat_status.message, cometchat_status.status
FROM buddy
if(buddy.penpalA = 887){
JOIN exchange ON buddy.penpalA = exchange.id
}ELSE{
JOIN exchange ON buddy.penpalB = exchange.id
}
LEFT JOIN cometchat_status ON exchange.id = cometchat_status.userid
if(buddy.penpalA = 887){
WHERE buddy.penpalB =887
}ELSE{
WHERE buddy.penpalA =887
}
ORDER BY username ASC
@Yuck,'case'不會有效這裏。 – 2012-01-18 19:27:05
最後的IF子句,無論我讀了多少次都沒有意義。如果好友,penpalA = 887 - 那麼你希望penpalB被檢查,否則檢查penpala是887--這有點圓。 – Andrew 2012-01-18 19:37:33
@Andrew:對,這一定是:'WHERE penpalA = 887 AND penpalB = 887',因爲'else'條件永遠不會被滿足。 – 2012-01-18 20:05:44