Microsoft SQL server 中 joined table 的列去掉方括号和大括号

Question

我正在使用 Microsoft SQL 服务器 v14.0.1000 我正在使用以下查询将我的查询结果转换为 JSON :

SELECT TOP(5) dn.id AS ID,
       dn.EventTimeStamp AS EventTimeStamp,
       dn.ControllerId AS ControllerID,
       JSON_QUERY((SELECT ControllerName
                     FROM Controllers
                    WHERE dn.ControllerId = Controllers.ControllerID
                      FOR JSON PATH, without_array_wrapper)) AS ControllerName
  FROM DashboardNotifications dn
 ORDER BY dn.ID DESC
   FOR JSON PATH

结果如下 JSON :

[
  {
    "ID": 354,
    "EventTimeStamp": "2022-05-17T05:35:25",
    "ControllerId": 24,
    "ControllerName": {
      "ControllerName": "P25-SC-0233"
    }
  },
  {
    "ID": 353,
    "EventTimeStamp": "2022-05-17T05:34:20",
    "ControllerId": 17,
    "ControllerName": {
      "ControllerName": "P25-SC-0226"
    }
  },
  {
    "ID": 352,
    "EventTimeStamp": "2022-05-17T05:33:50",
    "ControllerId": 16,
    "ControllerName": {
      "ControllerName": "P25-SC-0225"
    }
  }
]

我已经能够从

中删除方括号

"ControllerName":[{"ControllerName":"P25-SC-0233"}],

虽然我想要的输出是：

[
  {
    "ID": 354,
    "EventTimeStamp": "2022-05-17T05:35:25",
    "ControllerId": 24,
    "ControllerName": "P25-SC-0233"
  },
  {
    "ID": 353,
    "EventTimeStamp": "2022-05-17T05:34:20",
    "ControllerId": 17,
    "ControllerName": "P25-SC-0226"
  },
  {
    "ID": 352,
    "EventTimeStamp": "2022-05-17T05:33:50",
    "ControllerId": 16,
    "ControllerName": "P25-SC-0225"
  }
]

我需要做哪些更改才能删除嵌套的 ControllerName 键？

Answer 1

我想你只是想要没有 FOR JSON 的子查询（然后你不需要 JSON_QUERY 来转义它）

SELECT TOP(5) dn.id AS ID,
       dn.EventTimeStamp AS EventTimeStamp,
       dn.ControllerId AS ControllerID,
       (
           SELECT c.ControllerName
             FROM Controllers c
            WHERE dn.ControllerId = c.ControllerID
       ) AS ControllerName
  FROM DashboardNotifications dn
 ORDER BY dn.ID DESC
   FOR JSON PATH;

Ensure your subquery is guaranteed to return a maximum of one row

您也可以只使用连接

SELECT TOP(5) dn.id AS ID,
       dn.EventTimeStamp,
       dn.ControllerId,
       c.ControllerName
  FROM DashboardNotifications dn
  LEFT JOIN
       Controllers c ON dn.ControllerId = c.ControllerID
 ORDER BY dn.ID DESC
   FOR JSON PATH;

Answer 2

完全没有必要json_query。将查询更改为：

SELECT TOP(5) dn.id AS ID, dn.EventTimeStamp AS EventTimeStamp, dn.ControllerId AS ControllerID, (
    SELECT ControllerName FROM Controllers WHERE dn.ControllerId = Controllers.ControllerID
) AS ControllerName
FROM DashboardNotifications dn
ORDER BY dn.ID DESC
FOR JSON PATH

Microsoft SQL server 中 joined table 的列去掉方括号和大括号

Remove the square and curly brackets from the column of joined table in Microsoft SQL server

sql

sql-server

json

sql-server-2008

json-query