sql - 比较sql中的逗号分隔值

Question

我正在尝试编写一个函数来比较 SQL 中的逗号分隔值我从互联网上获取了一些代码:

SELECT CASE WHEN EXISTS 
(
  SELECT 1 FROM dbo.Split(@v1)
  WHERE ', ' + LTRIM(@v2) + ',' 
  LIKE '%, ' + LTRIM(Item) + ',%'
) THEN 1 ELSE 0 END;

然后我做一个函数:

CREATE FUNCTION [dbo].[fnCompareCSVString] 
(   
    @str1 nvarchar(50),
    @str2 nvarchar(50)
)

RETURNS  int
AS
BEGIN
    SELECT CASE WHEN EXISTS 
    (
       SELECT 1 FROM dbo.Split(@str1)
       WHERE ', ' + LTRIM(@str2) + ',' 
         LIKE '%, ' + LTRIM(Item) + ',%'
    ) THEN 1 ELSE 0 END;
END

我不擅长 SQL 我知道这是错误的

问题:

我想写一个比较逗号分隔值的函数，比较后将取两个值(逗号分隔值)，返回值将为真或假

我必须在此 SQL 函数中做哪些更改？

Answer 1

这是您要找的吗？

真/假结果

-- matches only those values which exist in both CSV sets
SELECT T1.[Item], CASE  WHEN T2.[Item] IS NULL THEN 0 ELSE 1 END AS [Match] 
FROM [dbo].[Split]('val1,val2,val3', ',') AS T1
    LEFT JOIN [dbo].[Split]('val3,val4', ',') AS T2 on T1.[Item] = T2.[Item]

返回

Item    Match
val1    0
val2    0
val3    1

只有真实匹配

-- matches only those values which exist in both CSV sets
SELECT T1.[Item] 
FROM [dbo].[Split]('val1,val2,val3', ',') AS T1
    INNER JOIN [dbo].[Split]('val3,val4', ',') AS T2 on T1.[Item] = T2.[Item]

返回

Item
val3

拆分函数

CREATE FUNCTION [dbo].[Split] 
(   
    @s VARCHAR(max),
    @split CHAR(1)
)
RETURNS @temptable TABLE ([Item] VARCHAR(MAX))    
AS
BEGIN
    DECLARE @x XML

    SELECT @x = CONVERT(xml,'<root><s>' + REPLACE(@s,@split,'</s><s>') + '</s></root>');

    INSERT INTO @temptable          
    SELECT [Value] = T.c.value('.','varchar(20)')
    FROM @X.nodes('/root/s') T(c);
RETURN
END;