SQL 开发知识：SqlServer将查询结果转换为XML和JSON

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;

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;