SqlServer将查询结果转换为XML和JSON

很久之前用到的，现在整理在这，里面一些代码来源于网上，不过有些bug已被我修改了。

1.查询结果转XML

DECLARE @ParameterSQL NVARCHAR(MAX)='SELECT * FROM table';
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))
SELECT @XML;
SELECT @XMLString;

其中@ParameterSQL为要查询的语句，@XMLXML格式数据，@XMLStringXML转成字符串

2.查询结果转JSON

查询结果转换成json需要经过两个步骤，首先将查询结果转成XML数据，然后通过XML数据转成json

XML转JSON的存储过程如下：

CREATE PROCEDURE [dbo].[SerializeJSON] (
   @XML XML,
   @json_xml NVARCHAR(MAX) OUTPUT
  )
AS
BEGIN
  DECLARE @XMLString NVARCHAR(MAX);
  SET @XMLString = CAST(@XML AS NVARCHAR(MAX));
  BEGIN TRY--//开始捕捉异常
    DECLARE @JSON NVARCHAR(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);
        DECLARE @end INT = CHARINDEX('/>', @Row, @FieldStart);
        IF @end<1
          OR @end>@FieldEnd
        BEGIN
          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 + '",';
        END;
        SET @FieldStart = @FieldStart + LEN(@StartField);
        SET @FieldEnd = CHARINDEX(@EndField, @Row, @FieldStart);
        SET @FieldStart = CHARINDEX(@StartField, @Row, @FieldEnd);
      END;
      IF LEN(@JSON)>0
        SET @JSON = SUBSTRING(@JSON, 0, LEN(@JSON));
      SET @JSON = @JSON + '},';
      --// for each row
      SET @RowStart = CHARINDEX(@StartRoot, @XMLString, @RowEnd);
    END;
    IF LEN(@JSON)>0
      SET @JSON = SUBSTRING(@JSON, 0, LEN(@JSON));
    --//SET @JSON = '[' + @JSON + ']';
    SET @json_xml = @JSON;
  END TRY--//结束捕捉异常
  BEGIN CATCH--//有异常被捕获
    SET @json_xml = @XMLString;
  END CATCH;--//结束异常处理
END;