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如何获取省份和城市

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Jun 13, 2016 pm 12:10 PM

nbspproselect

怎么获取省份和城市？
id pid paths  pro  city
1   0   0     中国
2   1   1,2   湖南
3   1   1,3   湖北
4   2   1,2,1 湖南  长沙
5   2   1,2,2 湖南  娄底
6   3   1,3,1 湖北  武汉

最后结果：

湖南   长沙  娄底
湖北   武汉

忙了一天晕了，好难弄

------解决思路----------------------

select pro, group_concat(city order by paths) as city<br />  from表<br />  where city!=''<br />  group by pro<br />

<br />pro city <br />湖北 武汉 <br />湖南 长沙,娄底 <br />

------解决思路----------------------
1、你展示的数据和结果没有体现出无限分类
2、你没有说明查询的依据是什么
3、在邻接列表算法中，并不需要冗余的 paths 列
    递归和不递归的算法，精华区都有
4、你的 paths 列含义不清，尤其是表示 ctiy 层次的值
5、按我国的行政区划标准，只有省、市、县、乡 4个层次
加上国家和村，也就是6个层次，不能说是无限分类，并且变化的概率很小
所以应按预排序遍历树算法组织数据

------解决思路----------------------
你是不是想这样体现无限循环的。

id pid paths  pro  city
1   0   0,     中国
2   1   1,2,   湖南
3   1   1,3,   湖北
4   2   1,2,4, 湖南  长沙
5   2   1,2,5, 湖南  娄底
6   3   1,3,6, 湖北  武汉

取湖南省下的所有市

SELECT `city` FROM  `pro` WHERE instr(`paths`,'1,2,')

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