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MySQL update join优化update in的查询效率

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  对单表执行更新没有什么好说的,无非就是update table_name set col1 = xx,col2 = yy where col = zz,主要就是where条件的设置。有时候更新某个表可能会涉及到多张数据表,例如:

update table_1 set score = score + 5 where uid in (select uid from table_2 where sid = 10);

  其实update也可以用到left join、inner join来进行关联,执行效率更高,把上面的sql替换成join的方式如下:

update table_1 t1 inner join table_2 t2 on t1.uid = t2.uid set score = score + 5 where t2.sid = 10;