How do I avoid character encoding when using “FOR XML PATH”?

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执念已碎
执念已碎 2020-12-08 02:06

I\'m looking to create a comma-separated list of values from a SQL Server 2005 table, just like in JanetOhara\'s question. I\'m using a query similar to the one presented i

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  • 2020-12-08 02:42

    You just need to use the right options with FOR XML. Here's one approach that avoids encoding:

    USE tempdb;
    GO
    
    CREATE TABLE dbo.x(y nvarchar(255));
    
    INSERT dbo.x SELECT 'Sports & Recreation'
       UNION ALL SELECT 'x >= y'
       UNION ALL SELECT 'blat'
       UNION ALL SELECT '<hooah>';
    
    -- BAD:
    SELECT STUFF((SELECT N',' + y
      FROM dbo.x 
      FOR XML PATH(N'')),1, 1, N'');
    
    -- GOOD:
    SELECT STUFF((SELECT N',' + y
      FROM dbo.x 
      FOR XML PATH, TYPE).value(N'.[1]', N'nvarchar(max)'),1, 1, N'');
    
    GO
    DROP TABLE dbo.x;
    

    If you are on a newer version of SQL Server (2017+), you can use STRING_AGG() and not worry about XML at all:

    SELECT STRING_AGG(y, N',') FROM dbo.x;
    

    db<>fiddle demonstrating all three.

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  • 2020-12-08 02:50

    See this post on Creating concatenated delimited string from a SQL result set and avoid character encoding when using “FOR XML PATH”

    An alternate approach would be to rely on concatenation of characters (of course sql is not great with string operations as it is developed to work with set theory)

    USE tempdb;
    GO 
    
    CREATE TABLE dbo.x ( y NVARCHAR(255) );
    INSERT dbo.x
    SELECT 'Sports & Recreation'
    UNION ALL
    SELECT 'x >= y'
    UNION ALL
    SELECT 'blat'
    UNION ALL
    SELECT '<hooah>';
    
    DECLARE @delimitedText varchar(max)
    SET @delimitedText=''
    SELECT @delimitedText += CASE WHEN LEN(@delimitedText) > 0 THEN +','+ y ELSE y END
    FROM dbo.x 
    
    SELECT @delimitedText
    GO
    DROP TABLE dbo.x;
    GO
    
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  • 2020-12-08 02:56

    You can also do this:

    -- BAD:
    SELECT STUFF((SELECT N',' + y
    FROM dbo.x 
    FOR XML PATH(N'')),1, 1, N'');
    
    -- GOOD:
    SELECT STUFF((SELECT N',' + y
    FROM dbo.x 
    FOR XML PATH(N''), TYPE).value('(./text())[1]','varchar(max)'),1, 1, N'');
    
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