很多时候都会用到多表查询,更新,删除,替换. MYSQL多表联合更新与SQL2000有所不同:
9 A" J* r0 f+ i9 Xselect a.studnt_sno,b.sno,c.grade from studnt as a inner join depart as b on a.sno=b.sno left join sc as c on b.cno=c.no) O5 h4 L0 t& Q. ^/ U& N# F
select col1, col2, col..., a.*, b.*,c.* from tableA a, tableB b,tableC c WHERE a.**_id = b.**_id AND b.**_id = c.**_id and a.**_id=c.**_idupdate tableA,tableB set tableA.colB= tableB.colB where tableA.colA= tableB.colA; " O/ b5 v% d* T+ p- C: K5 K
对应的SQL2000更新语句为: update tableA set tableA.colB=tableB.colB from tableA,tableB where tableA.colA=tableB.colA / q, n+ Q$ A. h0 m
更多的自己去扩展吧.. |