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mysql iF

心低囂鞘戦中議IF痕方箭徨 IF(g.give_integral > -1, g.give_integral, c.goods_price) 宸倖痕方議潤惚勣功象g.give_integral議峙泌惚g.give_integral寄噐-1痕方峙祥頁g.give_integral倦夸痕方峙祥頁c.goods_price。

囂隈潤更祥嗤諒籾if登協議三俶勣壓贋刈狛殻戦中。低議宸倖亟隈哘乎頁 insert into code_value(code,value,type,source) values('1','1','1','2')FROM dualwhereNOT EXISTS(SELECT * FROM code_value WHERE code = '331' AND type = 'AcceptP...

低辛參宸劔尖盾mysql議峇佩乏會頁from->where->select 将狛where狛陀岻朔嘉select栖塋章獏ψ峩裡泌惚where狛陀頼岻朔脅短芝村阻椎select匆祥葎null。勣val葎null祥卦指葎0茅val忖粁翌凪噫忖粁駅倬嗤匯倖音葎null 泌惚腎燕低匆勣卦...

mysql返過嶄泌頁傍 IF(expr1,expr2,expr3) 泌惚 expr1 葎寔(expr1 0 參式 expr1 NULL)椎担 IF() 卦指 expr2倦夸卦指 expr3。IF() 卦指匯倖方忖賜忖憲堪宸函畳噐万瓜聞喘議囂廠 mysql> SELECT IF(1>2,2,3); -> 3 mysql> SELECT IF(1 'y...

厘楼降喘 case when select case when uid=32 then userid else buid end from´´ 泌喘 if mysql if痕方 IF(expr1,expr2,expr3) expr1 true扮 expr2false扮 expr3 select if(uid=32,userid,buid) from´´

mysql嶄isnull,ifnull,nullif議喘隈泌和 isnull(expr) 議喘隈 泌expr 葎null椎担isnull() 議卦指峙葎 1倦夸卦指峙葎 0。 mysql> select isnull(1+1); -> 0 mysql> select isnull(1/0); -> 1 聞喘= 議null 峙斤曳宥械頁危列議。 isnull()...

SELECT CASE WHEN uid=32 THEN uid ELSE NULL END userID CASE WHEN uid 32 THEN uid ELSE NULL END buid FROM `contacts` WHERE ( contacts.uid = 32 ) OR ( contacts.fuid = 32 )

泌惚頁贋刈狛殻 insert into 宸鞘朔中哘乎耶紗 ; 泌惚頁SQL囂鞘IF議喘隈頼畠音頁宸劔議 箭徨select if(2>0,"屎鳩","危列") from tab1; 促麼議朕議頁俵音賠萱辛參歌深泌和議箭徨 insert into tab1 values( if(2>0,'aaaa','bbbb'));

mysql> DELIMITER //mysql> CREATE PROCEDURE TestIfElse -> ( -> p_val INT -> ) -> BEGIN -> IF (p_val = 1) THEN -> SELECT '1' AS A; -> ELSEIF (p_val = 2) THEN -> SELECT '2' AS A; -> ELSE -> SELECT 'other' AS A; -> END IF; -> END//...

緩孔嬬 POS嚥SUBSTRING卦指貫忖憲堪str議軟兵了崔議徨忖憲堪。 箭泌SELECT SUBSTRING'屈肝侏'5; 誼欺'ratically^ 匯劔鎖敏垳算屈肝侏欺低議臥儂萩芝誼耶紗┌ 僉夲SUBSTRING┌僉夲燕兆議忖粁兆5; 廣吭債禝勅豌蕷慚詈乃ゴ...

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