MS SQL读取JSON数据

前面有一篇《在SQL中直接把查询结果转换为JSON数据》https://www.cnblogs.com/insus/p/10905566.html，是把table转换为json。

现反过来，当SQL从前端接收过来的数据是JSON的话，需要把它转换为TABLE。在MS SQL Server 2016有一个方法，OPENJSON。

DECLARE @json_text NVARCHAR(MAX)
SET @json_text = 
 N'
 {
     "DB Type":
     [
        {"type":"AF","desc":"聚合函数(CLR)"},
        {"type":"F","desc":"FOREIGN KEY 约束"},
        {"type":"FN","desc":"SQL 标量函数"},
        {"type":"FS","desc":"程序集(CLR)标量函数"},
        {"type":"FT","desc":"程序集(CLR)表值函数"},
        {"type":"RF","desc":"复制筛选过程"},
        {"type":"IF","desc":"SQL 内联表值函数"},
        {"type":"TF","desc":"SQL 表值函数"}
     ]
 }'
   

读取JSON文本的key,value,type和type说明：

SELECT [key],[value],[type],[dbo].[svf_JSONDataType]([type]) AS data_type FROM  
OPENJSON (@json_text)  

下面是真正把JSON转TABLE:

SELECT [type],[desc] FROM  
OPENJSON (@json_text ,'$."DB Type"')  
WITH
(
    [type] NVARCHAR(20) '$.type',
    [desc] NVARCHAR(40) '$.desc'
)