我想使用sql Server 2016的For JSON功能获取带有整数数组的JSON.我对整数数组感到困惑.
数据库表结构：
declare @Employees table (ID int,Name nvarchar(50)) insert into @Employees values (1,'Bob'),(2,'Randy') declare @Permissions table (ID int,PermissionName nvarchar(50)) insert into @Permissions values (1,'Post'),'Comment'),(3,'Edit'),(4,'Delete') declare @EmployeePermissions table (EmployeeID int,PermissionID int) insert into @EmployeePermissions values (1,1),(1,2),3)
期望的结果：
{"EmployeePermissions": [
{"Employee":"Bob","Permissions":[1,2]},{"Employee":"Randy",2,3]}
}
这是我得到的最接近的,但不是我想要的.
select
e.Name as Employee,(select
convert(nvarchar(10),ep.PermissionID) as PermID
from @EmployeePermissions ep
where ep.EmployeeID=e.ID
for json path) as 'Permissions'
from
@Employees e
for json path,root('EmployeePermissions')
收益：
{"EmployeePermissions": [
{"Employee":"Bob","Permissions":[{"permID":1},{"permID":2}]},{"permID":2},{"permID":3}]}
}
解决方法
在AdventureWorks 2016 CTP3 JSON示例中,您可以找到一个可以清除键：值对的数组并创建数组od值的函数：
DROP FUNCTION IF EXISTS dbo.ufnToRawJsonArray
GO
CREATE FUNCTION
[dbo].[ufnToRawJsonArray](@json nvarchar(max),@key nvarchar(400)) returns nvarchar(max)
AS BEGIN
declare @new nvarchar(max) = replace(@json,CONCAT('},{"',@key,'":'),',')
return '[' + substring(@new,1 + (LEN(@key)+5),LEN(@new) -2 - (LEN(@key)+5)) + ']'
END
只需将SELECT FOR JSON表达式的结果作为@json参数和要作为第二个参数删除的键的名称.可能类似于：
select
e.Name as Employee,JSON_QUERY(dbo.ufnToRawJsonArray(
(select
convert(nvarchar(10),ep.PermissionID) as PermID
from @EmployeePermissions ep
where ep.EmployeeID=e.ID
for json path),'PermID'))
as 'Permissions'
from
@Employees e
for json path,root('EmployeePermissions')
