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这种查询要求的SQL语句应该怎么写

WBOY
Release： 2016-06-23 13:35:26
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表如下

A               B            
中国          1
中国          2
中国          3
美国          4
美国          5
英国          6
英国          7
.
.
.

-------------------最终查询出来结果要求是下面这样的
中国             1，2，3
美国             4，5
英国             6，7

我之前过直接用GROUP BY ，但A字段是能分组出来，但B字段的集合怎么出现呀？难道要再嵌一个SQL？？？


回复讨论(解决方案)

select A, group_concat(B) as B from 表 group by A
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select A, group_concat(B) as B from 表 group by A
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果然好用，但有点新问题，字段里同一组有相同值的B，如
A               B            
中国          1
中国          2
中国          1
中国          2
中国          1
-------------------------能显示成吗？我先研究一下上面的group_concat，说不定自己就能解决了，哈哈------------------------
中国          1，2

用了[DISTINCT]，好用，谢谢楼上，结分

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这种查询要求的SQL语句应该怎么写
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