SELECT * , sum( vew.price ) AS money, pt.ptid AS pptid
FROM `nb_panytask` pt
LEFT JOIN `nb_company` cp ON ( pt.cpid = cp.cpid )
LEFT JOIN (SELECT t.price, t.ptid, ut . *
FROM `nb_userstask` ut
LEFT JOIN `nb_task` t ON ( t.tid = ut.tid )
WHERE ut.status =4
)vew ON ( pt.ptid = vew.ptid )
GROUP BY pt.ptid那位大哥帮忙解释下这条语句
FROM `nb_panytask` pt
LEFT JOIN `nb_company` cp ON ( pt.cpid = cp.cpid )
LEFT JOIN (SELECT t.price, t.ptid, ut . *
FROM `nb_userstask` ut
LEFT JOIN `nb_task` t ON ( t.tid = ut.tid )
WHERE ut.status =4
)vew ON ( pt.ptid = vew.ptid )
GROUP BY pt.ptid那位大哥帮忙解释下这条语句
其中左链接两次.
第一次 nb_company 条件是cpid 相等
第二次 链接的是一子查询. 条件是ptid相等.
子查询 又一次左链接, 条件tid相等,并且过滤除status=4的所有记录