使用SQL Server,我如何分割一个字符串,以便我可以访问项目x?
拿一根“你好,约翰·史密斯”的绳子。我如何通过空格分割字符串并访问索引1应该返回“约翰”的项目?
使用SQL Server,我如何分割一个字符串,以便我可以访问项目x?
拿一根“你好,约翰·史密斯”的绳子。我如何通过空格分割字符串并访问索引1应该返回“约翰”的项目?
当前回答
如果任何人只想获得分离文本的一部分,可以使用这个
select * from from splitstringsep ('Word1 word2 word3',' ')
CREATE function [dbo].[SplitStringSep]
(
@str nvarchar(4000),
@separator char(1)
)
returns table
AS
return (
with tokens(p, a, b) AS (
select
1,
1,
charindex(@separator, @str)
union all
select
p + 1,
b + 1,
charindex(@separator, @str, b + 1)
from tokens
where b > 0
)
select
p-1 zeroBasedOccurance,
substring(
@str,
a,
case when b > 0 then b-a ELSE 4000 end)
AS s
from tokens
)
其他回答
在我看来,你们把事情搞得太复杂了。只需要创建一个CLR UDF就可以了。
using System;
using System.Data;
using System.Data.SqlClient;
using System.Data.SqlTypes;
using Microsoft.SqlServer.Server;
using System.Collections.Generic;
public partial class UserDefinedFunctions {
[SqlFunction]
public static SqlString SearchString(string Search) {
List<string> SearchWords = new List<string>();
foreach (string s in Search.Split(new char[] { ' ' })) {
if (!s.ToLower().Equals("or") && !s.ToLower().Equals("and")) {
SearchWords.Add(s);
}
}
return new SqlString(string.Join(" OR ", SearchWords.ToArray()));
}
};
基于纯集的解决方案,使用TVF和递归CTE。您可以将此函数JOIN和APPLY到任何数据集。
create function [dbo].[SplitStringToResultSet] (@value varchar(max), @separator char(1))
returns table
as return
with r as (
select value, cast(null as varchar(max)) [x], -1 [no] from (select rtrim(cast(@value as varchar(max))) [value]) as j
union all
select right(value, len(value)-case charindex(@separator, value) when 0 then len(value) else charindex(@separator, value) end) [value]
, left(r.[value], case charindex(@separator, r.value) when 0 then len(r.value) else abs(charindex(@separator, r.[value])-1) end ) [x]
, [no] + 1 [no]
from r where value > '')
select ltrim(x) [value], [no] [index] from r where x is not null;
go
用法:
select *
from [dbo].[SplitStringToResultSet]('Hello John Smith', ' ')
where [index] = 1;
结果:
value index
-------------
John 1
这里有一个UDF可以做到这一点。它将返回一个带分隔符的值的表,我还没有尝试所有的场景,但您的示例工作良好。
CREATE FUNCTION SplitString
(
-- Add the parameters for the function here
@myString varchar(500),
@deliminator varchar(10)
)
RETURNS
@ReturnTable TABLE
(
-- Add the column definitions for the TABLE variable here
[id] [int] IDENTITY(1,1) NOT NULL,
[part] [varchar](50) NULL
)
AS
BEGIN
Declare @iSpaces int
Declare @part varchar(50)
--initialize spaces
Select @iSpaces = charindex(@deliminator,@myString,0)
While @iSpaces > 0
Begin
Select @part = substring(@myString,0,charindex(@deliminator,@myString,0))
Insert Into @ReturnTable(part)
Select @part
Select @myString = substring(@mystring,charindex(@deliminator,@myString,0)+ len(@deliminator),len(@myString) - charindex(' ',@myString,0))
Select @iSpaces = charindex(@deliminator,@myString,0)
end
If len(@myString) > 0
Insert Into @ReturnTable
Select @myString
RETURN
END
GO
你可以这样称呼它:
Select * From SplitString('Hello John Smith',' ')
编辑:使用len>1处理分隔符的更新解决方案如下:
select * From SplitString('Hello**John**Smith','**')
Alter Function dbo.fn_Split
(
@Expression nvarchar(max),
@Delimiter nvarchar(20) = ',',
@Qualifier char(1) = Null
)
RETURNS @Results TABLE (id int IDENTITY(1,1), value nvarchar(max))
AS
BEGIN
/* USAGE
Select * From dbo.fn_Split('apple pear grape banana orange honeydew cantalope 3 2 1 4', ' ', Null)
Select * From dbo.fn_Split('1,abc,"Doe, John",4', ',', '"')
Select * From dbo.fn_Split('Hello 0,"&""&&&&', ',', '"')
*/
-- Declare Variables
DECLARE
@X xml,
@Temp nvarchar(max),
@Temp2 nvarchar(max),
@Start int,
@End int
-- HTML Encode @Expression
Select @Expression = (Select @Expression For XML Path(''))
-- Find all occurences of @Delimiter within @Qualifier and replace with |||***|||
While PATINDEX('%' + @Qualifier + '%', @Expression) > 0 AND Len(IsNull(@Qualifier, '')) > 0
BEGIN
Select
-- Starting character position of @Qualifier
@Start = PATINDEX('%' + @Qualifier + '%', @Expression),
-- @Expression starting at the @Start position
@Temp = SubString(@Expression, @Start + 1, LEN(@Expression)-@Start+1),
-- Next position of @Qualifier within @Expression
@End = PATINDEX('%' + @Qualifier + '%', @Temp) - 1,
-- The part of Expression found between the @Qualifiers
@Temp2 = Case When @End < 0 Then @Temp Else Left(@Temp, @End) End,
-- New @Expression
@Expression = REPLACE(@Expression,
@Qualifier + @Temp2 + Case When @End < 0 Then '' Else @Qualifier End,
Replace(@Temp2, @Delimiter, '|||***|||')
)
END
-- Replace all occurences of @Delimiter within @Expression with '</fn_Split><fn_Split>'
-- And convert it to XML so we can select from it
SET
@X = Cast('<fn_Split>' +
Replace(@Expression, @Delimiter, '</fn_Split><fn_Split>') +
'</fn_Split>' as xml)
-- Insert into our returnable table replacing '|||***|||' back to @Delimiter
INSERT @Results
SELECT
"Value" = LTRIM(RTrim(Replace(C.value('.', 'nvarchar(max)'), '|||***|||', @Delimiter)))
FROM
@X.nodes('fn_Split') as X(C)
-- Return our temp table
RETURN
END
下面的示例使用递归CTE
更新18.09.2013
CREATE FUNCTION dbo.SplitStrings_CTE(@List nvarchar(max), @Delimiter nvarchar(1))
RETURNS @returns TABLE (val nvarchar(max), [level] int, PRIMARY KEY CLUSTERED([level]))
AS
BEGIN
;WITH cte AS
(
SELECT SUBSTRING(@List, 0, CHARINDEX(@Delimiter, @List + @Delimiter)) AS val,
CAST(STUFF(@List + @Delimiter, 1, CHARINDEX(@Delimiter, @List + @Delimiter), '') AS nvarchar(max)) AS stval,
1 AS [level]
UNION ALL
SELECT SUBSTRING(stval, 0, CHARINDEX(@Delimiter, stval)),
CAST(STUFF(stval, 1, CHARINDEX(@Delimiter, stval), '') AS nvarchar(max)),
[level] + 1
FROM cte
WHERE stval != ''
)
INSERT @returns
SELECT REPLACE(val, ' ','' ) AS val, [level]
FROM cte
WHERE val > ''
RETURN
END
演示SQLFiddle