Re: How to Optimize distinct with index

[Darryle Steplight]

Select user_id from user where key1=value and
key2=value2 and key3=value2 GROUP BY user_id

 is faster than


Select distinct user_id from user where key1=value and
key2=value2 and key3=value2;


2009/6/18 周彦伟 <yanwei.zhou@stripped>:
> Hi,
>        I have a sql :
>                Select distinct user_id from user where key1=value and
> key2=value2 and key3=value2;
>
> I add index on (key1,key2,key3,user_id), this sql use temporary table
> howevery
> I have thousands of queries per second.
> How to optimize it?
>
>
> Anthoer question:
> Select * from user where user_id in(id1,id2,id3,id4,.....) order by use_id;
> I add index on user_id,but after in,order use temporary table, How to
> optimize it?
>
> Thanks!
>
> zhouyanwei
>
>
>
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