SQL Server表转json
我正在寻找拉表的某些列(Col1和2)并以JSON格式放置,并且还在每个节点中编写一些硬编码的JSON,就像这样。
{“ col1”:“ xxxx”,“ col2”:“ xxxx”,“ hardcodedString”:“ xxxx”,“
hardcodedString”:“ xxxx”,“ hardcodedString”:“ xxxx”,“ hardcodedString”:“
xxxx”,“ hardcodedString“:” xxxx“},
我发现以下git脚本,它创建了一个应该生成JSON的SP,但是当我按要求执行时,我得到“成功完成命令”
有什么想法可以输出结果,或者是否有更好的方法来实现JSON?
create procedure [dbo].[GetJSON] ( @schema_name varchar(50),
@table_name varchar(50),
@registries_per_request smallint = null
)
as
begin
if ( ( select count(*) from information_schema.tables where table_schema = @schema_name and table_name = @table_name ) > 0 )
begin
declare @json varchar(max),
@line varchar(max),
@columns varchar(max),
@sql nvarchar(max),
@columnNavigator varchar(50),
@counter tinyint,
@size varchar(10)
if (@registries_per_request is null)
begin
set @size = ''
end
else
begin
set @size = 'top ' + convert(varchar, @registries_per_request)
end
set @columns = '{'
declare schemaCursor cursor for
select column_name
from information_schema.columns
where table_schema = @schema_name
and table_name = @table_name
open schemaCursor
fetch next from schemaCursor into @columnNavigator
select @counter = count(*)
from information_schema.columns
where table_schema = @schema_name
and table_name = @table_name
while @@fetch_status = 0
begin
set @columns = @columns + '''''' + @columnNavigator + ''''':'''''' + convert(varchar, ' + @columnNavigator + ') + '''''''
set @counter = @counter - 1
if ( 0 != @counter )
begin
set @columns = @columns + ','
end
fetch next from schemaCursor into @columnNavigator
end
set @columns = @columns + '}'
close schemaCursor
deallocate schemaCursor
set @json = '['
set @sql = 'select ' + @size + '''' + @columns + ''' as json into tmpJsonTable from [' + @schema_name + '].[' + @table_name + ']'
exec sp_sqlexec @sql
select @counter = count(*) from tmpJsonTable
declare tmpCur cursor for
select * from tmpJsonTable
open tmpCur
fetch next from tmpCur into @line
while @@fetch_status = 0
begin
set @counter = @counter - 1
set @json = @json + @line
if ( 0 != @counter )
begin
set @json = @json + ','
end
fetch next from tmpCur into @line
end
set @json = @json + ']'
close tmpCur
deallocate tmpCur
drop table tmpJsonTable
select @json as json
end
end
回答:
我不会真正建议这样做,在应用程序层中有很多更好的方法可以做到这一点,但是以下内容避免了循环,并且比当前方法更冗长:
CREATE PROCEDURE dbo.GetJSON @ObjectName VARCHAR(255), @registries_per_request smallint = nullAS
BEGIN
IF OBJECT_ID(@ObjectName) IS NULL
BEGIN
SELECT Json = '';
RETURN
END;
DECLARE @Top NVARCHAR(20) = CASE WHEN @registries_per_request IS NOT NULL
THEN 'TOP (' + CAST(@registries_per_request AS NVARCHAR) + ') '
ELSE ''
END;
DECLARE @SQL NVARCHAR(MAX) = N'SELECT ' + @Top + '* INTO ##T ' +
'FROM ' + @ObjectName;
EXECUTE SP_EXECUTESQL @SQL;
DECLARE @X NVARCHAR(MAX) = '[' + (SELECT * FROM ##T FOR XML PATH('')) + ']';
SELECT @X = REPLACE(@X, '<' + Name + '>',
CASE WHEN ROW_NUMBER() OVER(ORDER BY Column_ID) = 1 THEN '{'
ELSE '' END + Name + ':'),
@X = REPLACE(@X, '</' + Name + '>', ','),
@X = REPLACE(@X, ',{', '}, {'),
@X = REPLACE(@X, ',]', '}]')
FROM sys.columns
WHERE [Object_ID] = OBJECT_ID(@ObjectName)
ORDER BY Column_ID;
DROP TABLE ##T;
SELECT Json = @X;
END
注意:我已经更改了您的两部分对象名称(@schema和@table)以仅接受完整的对象名称。
想法是基本上使用SQL-
Server中的XML扩展将表转换为XML,然后仅将开始标记替换为{ColumnName:
并将结束标记替换为,
。然后,它需要再进行两次替换,才能停止在每行的最后一列中添加右括号,并,
从JSON字符串中删除最后一个。
以上是 SQL Server表转json 的全部内容, 来源链接: utcz.com/qa/422613.html