拆分列值心得
/*---------------------------------
-- Author : 分拆列值htl258(Tony)
-- Date : 2009-09-10 01:38:02
-- Version: Microsoft SQL Server 2008 (SP1) - 10.0.2531.0 (Intel X86)
Mar 29 2009 10:27:29
Copyright (c) 1988-2008 Microsoft Corporation
Enterprise Evaluation Edition on Windows NT 5.1 <X86> (Build 2600: Service Pack 2)
---------------------------------*/
IF OBJECT_ID('tb') IS NOT NULL
DROP TABLE tb
GO
CREATE TABLE tb (id INT,col VARCHAR(30))
INSERT INTO tb VALUES(1,'aa,bb')
INSERT INTO tb VALUES(2,'aaa,bbb,ccc')
GO
--1.2000/2005通用方法
SELECT
a.id,
col=SUBSTRING(a.col,number,CHARINDEX(',',a.col+',',number)-b.number)
FROM tb a
JOIN master..spt_values b
ON b.type='p'
--AND SUBSTRING(','+a.col,b.number,1)=',' --用此条件或下面的条件均可
AND CHARINDEX(',',','+a.col,number)=number
--结果:
/*
id col
----------- --------------------------------------------------
1 aa
1 bb
2 aaa
2 bbb
2 ccc
(5 行受影响)
*/
--2.2005以上新方法:
SELECT a.id,b.col
FROM (
SELECT id,col=CAST('<v>'+REPLACE(col,',','</v><v>')+'</v>' AS XML)
FROM tb
) AS a
OUTER APPLY (
SELECT C.value('.','varchar(50)') AS col --此处value必须为小写
FROM a.col.nodes('/v') AS T(C)
) AS b
--结果:
/*
id col
----------- --------------------------------------------------
1 aa
1 bb
2 aaa
2 bbb
2 ccc
(5 行受影响)
*/
--3.游标循环法:
DECLARE @t TABLE (id INT,col NVARCHAR(50))
DECLARE @id INT,@col nvarchar(200)
DECLARE c CURSOR FOR SELECT * FROM tb
OPEN c
FETCH NEXT FROM c INTO @id,@col
WHILE @@FETCH_STATUS = 0
BEGIN
WHILE CHARINDEX(',',@col)>0
BEGIN
INSERT @t SELECT @id,LEFT(@col,CHARINDEX(',',@col+',')-1)
SET @col=STUFF(@col,1,CHARINDEX(',',@col),'')
END
INSERT @t SELECT @id,LEFT(@col,CHARINDEX(',',@col+',')-1) --退出循环后插入最后获取的值
FETCH NEXT FROM c INTO @id,@col
END
CLOSE c
DEALLOCATE c
--查询
SELECT * FROM @t
--结果:
/*
id col
----------- --------------------------------------------------
1 aa
1 bb
2 aaa
2 bbb
2 ccc
(5 行受影响)
*/
--4.SQL2005 函数法:
IF OBJECT_ID('tb') IS NOT NULL
DROP TABLE tb
GO
CREATE TABLE tb (id INT,col VARCHAR(30))
INSERT INTO tb VALUES(1,'aa,bb')
INSERT INTO tb VALUES(2,'aaa,bbb,ccc')
GO
IF OBJECT_ID('f_str') IS NOT NULL
DROP FUNCTION f_str
GO
CREATE FUNCTION f_str(@str VARCHAR(20))
RETURNS @t TABLE(col VARCHAR(20))
AS
BEGIN
SET @str=@str+','
WHILE len(@str)>0
BEGIN
INSERT @t SELECT LEFT(@str,CHARINDEX(',',@str)-1)
SET @str=STUFF(@str,1,CHARINDEX(',',@str),'')
END
RETURN
END
GO
--调用查询
SELECT a.id,b.col
FROM tb a
CROSS APPLY f_str(a.col) b
/*
id col
----------- --------------------
1 aa
1 bb
2 aaa
2 bbb
2 ccc
(5 行受影响)
*/
--5.SQL2005函数法二:
IF OBJECT_ID('tb') IS NOT NULL
DROP TABLE tb
GO
CREATE TABLE tb (id INT,col VARCHAR(30))
INSERT INTO tb VALUES(1,'aa,bb')
INSERT INTO tb VALUES(2,'aaa,bbb,ccc')
GO
IF OBJECT_ID('f_str') IS NOT NULL
DROP FUNCTION f_str
GO
CREATE FUNCTION f_str(@str VARCHAR(50))
RETURNS @t TABLE(col VARCHAR(50))
AS
BEGIN
DECLARE @xml XML
SET @xml='<v>'+REPLACE(@str,',','</v><v>')+'</v>'
INSERT @t SELECT C.value('.','varchar(50)') FROM @xml.nodes('/v') AS T(C)
RETURN
END
GO
--调用查询
SELECT a.id,b.col
FROM tb a
CROSS APPLY f_str(a.col) b
/*
id col
----------- ------------------
1 aa
1 bb
2 aaa
2 bbb
2 ccc
(5 行受影响)
*/