left join – LPC影子技术分享 https://www.mudbest.com 行影不离,忘之却步. Tue, 12 Mar 2013 08:23:35 +0000 zh-Hans hourly 1 https://wordpress.org/?v=7.1.2 纠结的SQL https://www.mudbest.com/%e7%ba%a0%e7%bb%93%e7%9a%84sql/ Sat, 12 Mar 2011 12:38:41 +0000 http://www.mudbest.com/?p=461 阅读更多]]> 今天要查出一个统计列表，但又有时间条件，条件就是最后更新的一次为准确值，结果就冒出这么一段SQL出来了。还好，结果符合要求。

SELECT `dg`.`aid` ,`dg`.`title`,`dg`.`senddate`,`dg`.`mid`,`df`.`dtime` FROM `_addonlog` as `dg` LEFT JOIN `_feedback` as `df` on `dg`.`aid` = `df`.`aid` AND `dg`.`mid` = '88' Group by `df`.`aid` ORDER BY MAX(`df`.`dtime`)  DESC
]]> mysql left join查询 https://www.mudbest.com/mysql-left-join%e6%9f%a5%e8%af%a2/ Fri, 11 Mar 2011 08:04:00 +0000 http://www.mudbest.com/?p=457 阅读更多]]> SELECT * FROM `_bidding_tb` as `db` , `_member` AS dm LEFT JOIN `_member_emcee` AS de ON dm.mid = de.mid LEFT JOIN `_member_person` AS dp ON dm.mid = dp.mid WHERE dm.mtype<>'企业' AND `db`.`mid` = `dm`.`mid` AND `db`.`aid` = 221 
SELECT fb.*,mb.userid,mb.face as mface,mb.spacesta,mb.scores FROM `_feedback` fb left join `_member` mb on mb.mid = fb.mid where fb.aid='$aid' and fb.ischeck='1' order by fb.id desc limit 0, 50


SELECT v.*,m.uname,m.sex,face FROM `_member_vhistory` AS v  LEFT JOIN `_member` AS m ON v.vid=m.mid WHERE 条件 ORDER BY vtime DESC

由此可看出LEFT JOIN的强大之处，从左表向右表开始查询，在经过第二个表的时候用ON v.vid=m.mid来进行关联

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