sql查找某个字符串第N次出现的位置的函数(转帖)

if exists(select 1 from sysobjects where name='char_index')

drop function char_index

create function char_index(@string varchar(8000),@char varchar(10),@index smallint)

--@string:待查找字符串，@index:查找位置

returns smallint

as

begin

declare

@i tinyint,--当前找到第@i个

@position tinyint--所在位置

set @position=@index;

set @i=0;

while charindex(@char,@string,@position)>0

begin

set @position=charindex(@char,@string,@position)+1;

set @i=@i+1;

if @i=@index

begin

return @position-1;

end

end

return 0;--0表示未找到

end

select dbo.char_index('sdf_dsf_dfgdg_ertr_erte','f_',2)

--如何查找某个字符串第N次出现的位置,

--比如:字符串"sdf_dsf_dfgdg_ertr_erte",要查找"f_"第二次出现的位置

if object_id('f_findstr') is not null

drop function f_findstr

go

create function f_findstr(@s varchar(8000),@find varchar(10),@index int)

returns int

as

begin

declare @startindex int

set @startindex=0

while @index>0

begin

if charindex(@find,@s,@startindex)>0

set @startindex=charindex(@find,@s,@startindex+1)

set @index=@index-1

end

return @startindex

end

go

select dbo.f_findstr('sdf_dsf_dfgdg_ertr_erte','f_',2)

use test

go

if exists (select * from dbo.sysobjects where id = object_id(N'[dbo].[F_Str]') and xtype in (N'FN', N'IF', N'TF'))

drop function [dbo].[F_Str]

GO

CREATE FUNCTION dbo.F_Str(

@s varchar(8000),

@pos int,

@split varchar(10)

)RETURNS int

AS

BEGIN

IF @s IS NULL RETURN(NULL)

DECLARE @splitlen int,@i int

SELECT @splitlen=LEN(@split+'a')-2,@i=0

WHILE @pos>1 AND CHARINDEX(@split,@s+@split)>0

SELECT @pos=@pos-1,@i=@i+CHARINDEX(@split,@s+@split)+@splitlen,

@s=STUFF(@s,1,CHARINDEX(@split,@s+@split)+@splitlen,'')

RETURN(@i+CHARINDEX(@split,@s+@split))

END

GO

declare @s nvarchar(100)

select @s='sdf_dsf_dfgdg_ertr_erte'

select dbo.F_Str(@s,2,'f_')

-----------

7

(1 行受影响)

方法4

if exists(select 1 from sysobjects where name='char_index')

drop function char_index

go

create function char_index(@string varchar(8000),@char varchar(10),@index smallint)

--@string:待查找字符串，@index:查找位置

returns smallint

as

begin

declare

@i int,--当前找到第@i个

@position int--所在位置

set @position=1;

set @i=0;

while charindex(@char,@string,@position)>0

begin

set @position=charindex(@char,@string,@position)+1;

set @i=@i+1;

if @i=@index

begin

return @position-1;

end

end

return 0;--0表示未找到

end

go