分别为每条记录获取 SQL 服务器记录详细信息为 JSON

Question

我有 2 张桌子。 部门和员工如下：

    Department
    |----------------------|
    |   Id    |   Name     |
    |---------|------------|
    |   10    |    Admin   |
    |---------|------------|
    |   11    |    IT      |
    |---------|------------|

    Employee
    |----------------------|--------------|
    |   Id    |   Name     | DepartmentId |
    |---------|------------|--------------|
    |   1     |    Peter   |    10        |
    |---------|------------|--------------|
    |   2     |    Scott   |    11        |
     --------------------------------------

我需要每个部门的 JSON 详细信息，如下所示：

|----------------------|------------------------------------------------------------ |
|   DepartmentId       |   JSONDeatails                                              |
|--------------------- |------------------------------------------------------------ |
|   10                 |{"id": 10,"name": "Admin","Emp": [{"Id": 1,"name": "peter"}]}|
|----------------------|-------------------------------------------------------------|
|   11                 |{"id": 11,"name": "IT","Emp":[{"Id": 2,"name": "scott"}]}    |
|----------------------|-------------------------------------------------------------|

我尝试了下面的查询，它将整个表数据作为一个 JSON 返回。

 SELECT     D.Id, D.name, Emp.Id, Emp.Name FROM Department D
 LEFT JOIN Employee Emp ON D.Id= Emp.DepartmentId FOR JSON AUTO

我收到如下回复：

JSON_F52E2B61-18A1-11d1-B105-00805F49916B
[{"id": 10,"name": "Admin","Emp": [{"Id": 1,"name": "peter"}]},{"id": 11,"name": "IT","Emp":[{"Id": 2,"name": "scott"}]}]

Answer 1

经过多次试验，我可以找出为每条记录提供 JSON 的查询。 这里是：

SELECT D.Id, 
     (SELECT Di.Id, Di.name ,Emp.Id, Emp.Name FROM Department Di 
        LEFT JOIN Employee Emp ON Di.Id= Emp.DepartmentId 
        WHERE Di.Id = D.id FOR JSON AUTO) AS Details 
FROM Department D