标签：
数据库环境：SQL SERVER 2005
我们实现将同一组的数据内容合并到一行的时候，可以通过FOR XML PATH来实现。
有数据如图1，要实现图2的效果
1.图1到图2的FOR XML PATH实现
网上有很多介绍FOR XML的方法，这里不再细说，感兴趣的朋友可以去查询一下它的用法。
--数据准备 ;WITH x0 AS ( SELECT 1 AS id , ‘001‘ AS ty UNION ALL SELECT 1 AS id , ‘002‘ AS ty UNION ALL SELECT 2 AS id , ‘003‘ AS ty UNION ALL SELECT 3 AS id , ‘004‘ AS ty UNION ALL SELECT 3 AS id , ‘1234‘ AS ty UNION ALL SELECT 4 AS id , ‘01‘ AS ty UNION ALL SELECT 4 AS id , ‘005‘ AS ty UNION ALL SELECT 4 AS id , ‘006‘ AS ty ) /*实现*/ SELECT id , STUFF(ty, 1, 1, ‘‘) AS ty FROM ( SELECT id , ( SELECT ‘,‘ + x2.ty FROM x0 x2 WHERE x2.id = x1.id FOR XML PATH(‘‘) ) AS ty FROM x0 x1 GROUP BY id ) t
2.图2到图1的递归实现
从图2到图1，实现的方法不止递归一种方法，各位可以试着用其它方法解决。
/*准备数据*/ WITH x0 AS ( SELECT 1 AS id , ‘001,002‘ AS ty UNION ALL SELECT 2 AS id , ‘003‘ AS ty UNION ALL SELECT 3 AS id , ‘004,1234‘ AS ty UNION ALL SELECT 4 AS id , ‘01,005,006‘ AS ty ), x1 ( id, ty1, ty2 ) AS ( SELECT id , CASE WHEN CHARINDEX(‘,‘, ty, 1) > 0 THEN CONVERT(VARCHAR(10), LEFT(ty, CHARINDEX(‘,‘, ty, 1) - 1)) ELSE ty END AS ty1 ,--本次拆分字符 CASE WHEN CHARINDEX(‘,‘, ty, 1) > 0 THEN STUFF(ty + ‘,‘, 1, CHARINDEX(‘,‘, ty), ‘‘) ELSE NULL END AS ty2--待拆分字符串 FROM x0 UNION ALL SELECT id , CONVERT(VARCHAR(10), LEFT(ty2, NULLIF(CHARINDEX(‘,‘, ty2, 1), 0) - 1)) AS ty1 ,--本次拆分字符 STUFF(ty2, 1, CHARINDEX(‘,‘, ty2), ‘‘) AS ty2--待拆分字符串 FROM x1 WHERE CHARINDEX(‘,‘, ty2, 1) > 0 ) SELECT id,ty1 AS ty FROM x1 ORDER BY id
标签：
原文地址：http://www.cnblogs.com/boss-he/p/4748192.html
