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[转载]数据库中各种字符串的截取函数 – 妍珊 – 博客园.
今天看见有人再问数据库中的数据截取了，我就和大家分享一下我看过的一篇有关这方面的文章吧。
--各种字符串截取函数
if exists (select * from dbo.ss where id = object_id(N'[dbo].[f_splitSTR]') and xtype in (N'FN', N'IF', N'TF'))
drop function [dbo].[f_splitSTR]
GO
--1 循环截取法
CREATE FUNCTION f_splitSTR(
@s varchar(8000), --待分拆的字符串
@split varchar(10) --数据分隔符
)RETURNS @re TABLE(col varchar(100))
AS
BEGIN
DECLARE @splitlen int
SET @splitlen=LEN(@split+'a')-2
WHILE CHARINDEX(@split,@s)>0
BEGIN
INSERT @re VALUES(LEFT(@s,CHARINDEX(@split,@s)-1))
SET @s=STUFF(@s,1,CHARINDEX(@split,@s)+@splitlen,'')
END
INSERT @re VALUES(@s)
RETURN
END
GO
/*==============================================*/
if exists (select * from dbo.ss where id = object_id(N'[dbo].[f_splitSTR]') and xtype in (N'FN', N'IF', N'TF'))
drop function [dbo].[f_splitSTR]
GO
--2 使用临时性分拆辅助表法
CREATE FUNCTION f_splitSTR(
@s varchar(8000), --待分拆的字符串
@split varchar(10) --数据分隔符
)RETURNS @re TABLE(col varchar(100))
AS
BEGIN
--创建分拆处理的辅助表(用户定义函数中只能操作表变量)
DECLARE @t TABLE(ID int IDENTITY,b bit)
INSERT @t(b) SELECT TOP 8000 0 FROM syscolumns a,syscolumns b
INSERT @re SELECT SUBSTRING(@s,ID,CHARINDEX(@split,@s+@split,ID)-ID)
FROM @t
WHERE ID<=LEN(@s+'a')
AND CHARINDEX(@split,@split+@s,ID)=ID
RETURN
END
GO
/*==============================================*/
if exists (select * from dbo.ss where id = object_id(N'[dbo].[f_splitSTR]') and xtype in (N'FN', N'IF', N'TF'))
drop function [dbo].[f_splitSTR]
GO
if exists (select * from dbo.ss where id = object_id(N'[dbo].[tb_splitSTR]') and objectproperty(id,N'IsUserTable')=1)
drop table [dbo].[tb_splitSTR]
GO
--2.1 使用永久性分拆辅助表法
--字符串分拆辅助表
SELECT TOP 8000 ID=IDENTITY(int,1,1) INTO dbo.tb_splitSTR
FROM syscolumns a,syscolumns b
GO
--字符串分拆处理函数
CREATE FUNCTION f_splitSTR(
@s varchar(8000), --待分拆的字符串
@split varchar(10) --数据分隔符
)RETURNS TABLE
AS
RETURN(
SELECT col=CAST(SUBSTRING(@s,ID,CHARINDEX(@split,@s+@split,ID)-ID) as varchar(100))
FROM tb_splitSTR
WHERE ID<=LEN(@s+'a')
AND CHARINDEX(@split,@split+@s,ID)=ID)
GO
/*==============================================*/
if exists (select * from dbo.ss where id = object_id(N'[dbo].[f_splitSTR]') and xtype in (N'FN', N'IF', N'TF'))
drop function [dbo].[f_splitSTR]
GO
--3 将数据项按数字与非数字再次拆份
CREATE FUNCTION f_splitSTR(
@s varchar(8000), --待分拆的字符串
@split varchar(10) --数据分隔符
)RETURNS @re TABLE(No varchar(100),Value varchar(20))
AS
BEGIN
--创建分拆处理的辅助表(用户定义函数中只能操作表变量)
DECLARE @t TABLE(ID int IDENTITY,b bit)
INSERT @t(b) SELECT TOP 8000 0 FROM syscolumns a,syscolumns b
INSERT @re
SELECT No=REVERSE(STUFF(col,1,PATINDEX('%[^-^.^0-9]%',col+'a')-1,'')),
Value=REVERSE(LEFT(col,PATINDEX('%[^-^.^0-9]%',col+'a')-1))
FROM(
SELECT col=REVERSE(SUBSTRING(@s,ID,CHARINDEX(@split,@s+@split,ID)-ID))
FROM @t
WHERE ID<=LEN(@s+'a')
AND CHARINDEX(@split,@split+@s,ID)=ID)a
RETURN
END
GO
/*==============================================*/
if exists (select * from dbo.ss where id = object_id(N'[dbo].[f_splitSTR]') and xtype in (N'FN', N'IF', N'TF'))
drop function [dbo].[f_splitSTR]
GO
--3.1 分拆短信数据
CREATE FUNCTION f_splitSTR(@s varchar(8000))
RETURNS @re TABLE(split varchar(10),value varchar(100))
AS
BEGIN
DECLARE @splits TABLE(split varchar(10),splitlen as LEN(split))
INSERT @splits(split)
SELECT 'AC' UNION ALL
SELECT 'BC' UNION ALL
SELECT 'CC' UNION ALL
SELECT 'DC'
DECLARE @pos1 int,@pos2 int,@split varchar(10),@splitlen int
SELECT TOP 1
@pos1=1,@split=split,@splitlen=splitlen
FROM @splits
WHERE @s LIKE split+'%'
WHILE @pos1>0
BEGIN
SELECT TOP 1
@pos2=CHARINDEX(split,@s,@splitlen+1)
FROM @splits
WHERE CHARINDEX(split,@s,@splitlen+1)>0
ORDER BY CHARINDEX(split,@s,@splitlen+1)
IF @@ROWCOUNT=0
BEGIN
INSERT @re VALUES(@split,STUFF(@s,1,@splitlen,''))
RETURN
END
ELSE
BEGIN
INSERT @re VALUES(@split,SUBSTRING(@s,@splitlen+1,@pos2-@splitlen-1))
SELECT TOP 1
@pos1=1,@split=split,@splitlen=splitlen,@s=STUFF(@s,1,@pos2-1,'')
FROM @splits
WHERE STUFF(@s,1,@pos2-1,'') LIKE split+'%'
END
END
RETURN
END
GO
