十年后回顾,今天肯定有更好的方法来做到这一点。
SQL Server 2022、Azure SQL 数据库、托管实例
(example)
CREATE OR ALTER FUNCTION dbo.SplitWithPairs
(
@List nvarchar(max),
@MajorDelimiter varchar(3) = ',',
@MinorDelimiter varchar(3) = ':'
)
RETURNS TABLE WITH SCHEMABINDING
AS
RETURN
(
SELECT LeftItem = [1], RightItem = [2], Position
FROM
(
SELECT Position = o.ordinal,
value = TRIM(i.value),
i.ordinal
FROM STRING_SPLIT(@List, @MajorDelimiter, 1) AS o
CROSS APPLY STRING_SPLIT(o.value, @MinorDelimiter, 1) AS i
WHERE o.value > ''
) AS s PIVOT (MAX(value) FOR ordinal IN ([1],[2])) AS p
);
SQL Server 2016 - 2019
(example)
在 SQL Server 2016 到 2019 中,进行了一些更改:
-
STRING_SPLIT
在 SQL Server 2022 之前不支持序数,因此我们可以使用OPENJSON
instead
- 我们需要使用
LTRIM/RTRIM
since TRIM
在 SQL Server 2017 中添加
-
key
是从 0 开始的,所以我们增加 1 以获得等效的从 1 开始的位置
关于此功能的一个注意事项是您不能使用,
作为次定界符而不改变函数,因为,
is how OPENJSON
划定界限。您可能希望在这两个分隔符中保留其他字符。
CREATE OR ALTER FUNCTION dbo.SplitWithPairs
(
@List nvarchar(max),
@MajorDelimiter varchar(3) = ',',
@MinorDelimiter varchar(3) = ':' -- can't be ,
)
RETURNS TABLE WITH SCHEMABINDING
AS
RETURN
(
SELECT LeftItem = [1], RightItem = [2], Position
FROM
(
SELECT Position = o.[key] + 1,
value = LTRIM(RTRIM(i.value)),
ordinal = i.[key] + 1
FROM OPENJSON
(
CONCAT('["', REPLACE(STRING_ESCAPE(@List, 'JSON'),
@MajorDelimiter, '","'), '"]')
) AS o
CROSS APPLY OPENJSON
(
REPLACE(CONCAT('[', QUOTENAME(o.value, '"'), ']'),
@MinorDelimiter, '","')
) AS i
WHERE o.value > ''
) AS s PIVOT (MAX(value) FOR ordinal IN ([1],[2])) AS p
);
不再支持的版本
最后,原始答案适用于早于 SQL Server 2016 的版本,我将保持原样,但免责声明它可以改进(不乏阅读有关该内容的文章)here而且,一般来说,多语句表值函数(尤其是循环)是一个很大的危险信号):
CREATE FUNCTION [dbo].[SplitWithPairs]
(
@List NVARCHAR(MAX),
@MajorDelimiter VARCHAR(3) = ',',
@MinorDelimiter VARCHAR(3) = ':'
)
RETURNS @Items TABLE
(
Position INT IDENTITY(1,1) NOT NULL,
LeftItem INT NOT NULL,
RightItem INT NOT NULL
)
AS
BEGIN
DECLARE
@Item NVARCHAR(MAX),
@LeftItem NVARCHAR(MAX),
@RightItem NVARCHAR(MAX),
@Pos INT;
SELECT
@List = @List + ' ',
@MajorDelimiter = LTRIM(RTRIM(@MajorDelimiter)),
@MinorDelimiter = LTRIM(RTRIM(@MinorDelimiter));
WHILE LEN(@List) > 0
BEGIN
SET @Pos = CHARINDEX(@MajorDelimiter, @List);
IF @Pos = 0
SET @Pos = LEN(@List) + LEN(@MajorDelimiter);
SELECT
@Item = LTRIM(RTRIM(LEFT(@List, @Pos - 1))),
@LeftItem = LTRIM(RTRIM(LEFT(@Item,
CHARINDEX(@MinorDelimiter, @Item) - 1))),
@RightItem = LTRIM(RTRIM(SUBSTRING(@Item,
CHARINDEX(@MinorDelimiter, @Item)
+ LEN(@MinorDelimiter), LEN(@Item))));
INSERT @Items(LeftItem, RightItem)
SELECT @LeftItem, @RightItem;
SET @List = SUBSTRING(@List,
@Pos + LEN(@MajorDelimiter), DATALENGTH(@List));
END
RETURN;
END
GO
DECLARE @ValuePairs VARCHAR(MAX) = '1:1, 1:2, 1:4, 2:3,1000:230, 130:120,';
SELECT LeftItem, RightItem
FROM dbo.SplitWithPairs(@ValuePairs, ',', ':')
ORDER BY Position;
GO