请问sql语句，多表查询一对多分页

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Release： 2016-06-13 11:56:40

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请教sql语句，多表查询一对多分页
    三张表

    题目表topic,字段 to_id to_title

     知识点表tag,字段t_id t_title

     关联表relation,字段to_id t_id

     每个题目可以有多个知识点

      现web界面提供搜索框，每页10个小题，用户可以多选知识点，遇到的问题是，有重复的数据的

<br />select topic.to_id,topic.to_title from topic,relation where ( topic.to_id = relation.to_id )  and (t_id in (1,2,3)); <br />

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现在的情况是，如果知识点1,2,3都是对应to_id为1的，那么就会出现3道一样题目。可如果去掉重复的话，那么又和每页10条相悖了，特向前辈请教相关sql语句，不甚感激！！！
------解决方案--------------------
select distinct( topic.to_id,topic.to_title) from topic,relation ，tag where ( topic.to_id = relation.to_id ) and (t_id in (1,2,3)) limit 0,10;

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