sql语句优化之not in
2015-12-30 17:02:29

多表关联想查a表中除去b表的可用not exists 效率比not in 更高优化后的语句用时0.421秒select john.*,(casewhen round((case john.sumcountwhen 0 then0elsemycount * 100 / sumcountend),2) > 100 then100elseround((case john.sumcountwhen 0 then0elsemycount * 100 / sumcountend),2)end ......

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