SQL Server result to JSON stored procedure

SET ANSI_NULLS ON
 GO
 SET QUOTED_IDENTIFIER ON
 GO
 CREATE PROCEDURE[dbo].[SerializeJSON](
 @ParameterSQL AS VARCHAR(MAX)
 )
 AS
 BEGIN
  
 DECLARE @SQL NVARCHAR(MAX)
 DECLARE @XMLString VARCHAR(MAX)
 DECLARE @XML XML
 DECLARE @Paramlist NVARCHAR(1000)
 SET @Paramlist = N'@XML XML OUTPUT'
 SET @SQL = 'WITH PrepareTable (XMLString)'
 SET @SQL = @SQL + 'AS('
 SET @SQL = @SQL + @ParameterSQL+ 'FOR XML RAW,TYPE,ELEMENTS'
 SET @SQL = @SQL + ')'
 SET @SQL = @SQL + 'SELECT @XML=[XMLString]FROM[PrepareTable]'
 EXEC sp_executesql @SQL, @Paramlist, @XML=@XML OUTPUT
 SET @XMLString=CAST(@XML AS VARCHAR(MAX))
  
 DECLARE @JSON VARCHAR(MAX)
 DECLARE @Row VARCHAR(MAX)
 DECLARE @RowStart INT
 DECLARE @RowEnd INT
 DECLARE @FieldStart INT
 DECLARE @FieldEnd INT
 DECLARE @KEY VARCHAR(MAX)
 DECLARE @Value VARCHAR(MAX)
  
 DECLARE @StartRoot VARCHAR(100);SET @StartRoot='<row>'
 DECLARE @EndRoot VARCHAR(100);SET @EndRoot='</row>'
 DECLARE @StartField VARCHAR(100);SET @StartField='<'
 DECLARE @EndField VARCHAR(100);SET @EndField='>'
  
 SET @RowStart=CharIndex(@StartRoot,@XMLString,0)
 SET @JSON=''
 WHILE @RowStart>0
 BEGIN
     SET @RowStart=@RowStart+Len(@StartRoot)
     SET @RowEnd=CharIndex(@EndRoot,@XMLString,@RowStart)
     SET @Row=SubString(@XMLString,@RowStart,@RowEnd-@RowStart)
     SET @JSON=@JSON+'{'
  
     -- for each row
     SET @FieldStart=CharIndex(@StartField,@Row,0)
     WHILE @FieldStart>0
     BEGIN
         -- parse node key
         SET @FieldStart=@FieldStart+Len(@StartField)
         SET @FieldEnd=CharIndex(@EndField,@Row,@FieldStart)
         SET @KEY=SubString(@Row,@FieldStart,@FieldEnd-@FieldStart)
         SET @JSON=@JSON+'"'+@KEY+'":'
         -- parse node value
         SET @FieldStart=@FieldEnd+1
         SET @FieldEnd=CharIndex('</',@Row,@FieldStart)
         SET @Value=SubString(@Row,@FieldStart,@FieldEnd-@FieldStart)
         SET @JSON=@JSON+'"'+@Value+'",'
  
         SET @FieldStart=@FieldStart+Len(@StartField)
         SET @FieldEnd=CharIndex(@EndField,@Row,@FieldStart)
         SET @FieldStart=CharIndex(@StartField,@Row,@FieldEnd)
     END   
     IF LEN(@JSON)>0SET @JSON=SubString(@JSON,0,LEN(@JSON))
     SET @JSON=@JSON+'},'
     --/ for each row
  
     SET @RowStart=CharIndex(@StartRoot,@XMLString,@RowEnd)
 END
 IF LEN(@JSON)>0SET @JSON=SubString(@JSON,0,LEN(@JSON))
 SET @JSON='['+@JSON+']'
 SELECT @JSON
  
 --使用: EXEC [SerializeJSON] 'SELECT * FROM [xxx]'
 END
 GO