FOR XML PATH 应用及其反向分解

/*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