I run a SQL statement about UPDATE covering multiple tables, i feel that it is too slowly. SQL statement: update b_bb,tempdb set b_bb.zrk1=tempdb.num where b_bb.dwdm=concat(tempdb.shengbm,tempdb.shibm,tempdb.xianbm,tempdb.xiangbm,tempdb.cunbm); I modify the JOIN syntax like this:
update b_bb STRAIGHT_JOIN tempdb set b_bb.zrk1=tempdb.num where b_bb.dwdm=concat(tempdb.shengbm,tempdb.shibm,tempdb.xianbm,tempdb.xiangbm,tempdb.cunbm); It can be a little faster than before, but it is not be fast as i expected. I run a similar SQL statement on SQLServer2000, it is about 10 times faster than mysql. How to promote the execute efficiency of the UPDATE statement like this ?
