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:
6 n2 b7 K; b+ O4 H+ O4 Nselect 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: s+ h5 g8 r5 O$ p
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;
! p8 w1 }; \+ ~5 b- b) V2 j 对应的SQL2000更新语句为: update tableA set tableA.colB=tableB.colB from tableA,tableB where tableA.colA=tableB.colA
" J+ w+ O; U) t! l# e更多的自己去扩展吧.. |