为 UNION 重命名 JSON 列

Question

备注：我的例子过于简化了。实际上，我正在处理一个巨大的查询。但是为了说明问题/错误，让我们求助于苹果和橙子。

我的原始查询如下所示：

SELECT 'FruitsCount' AS "Type", (SELECT count(id) as Counter, [Name] FROM Fruits group by name FOR JSON PATH) AS "Value"

这会导致类似的结果。我们将其称为Format A

|---------------------|------------------------------------------------------------------------------|
|        Type         |                                   Value                                      |
|---------------------|------------------------------------------------------------------------------|
|     FruitCount      |         [{"Counter":2, "Name":"Apple"},{"Counter":3, "Name":"Orange"}]       |
|---------------------|------------------------------------------------------------------------------|

但是，现在我想创建水果和蔬菜计数的联合。我的查询现在看起来像这样

(SELECT count(id) as Counter, [Name] FROM Fruits group by name
UNION
SELECT count(id) as Counter, [Name] FROM Vegetables group by name)
FOR JSON PATH

|---------------------|------------------------------------------------------------------------------|
|                           JSON_F52E2B61-18A1-11d1-B105-00805F49916B                                |
|---------------------|------------------------------------------------------------------------------|
|     [{"Counter":2, "Name":"Apple"},{"Counter":3, "Name":"Orange"},{"Counter":7, "Name":"Tomato"}]  |
|---------------------|------------------------------------------------------------------------------|

但是，我希望它采用以前的格式，其中我有一个类型和值列（格式 A）。

我尝试了以下操作：

SELECT 'FruitsCount' AS "Type", ((SELECT count(id) as Counter, [Name] FROM Fruits group by name
UNION
SELECT count(id) as Counter, [Name] FROM Vegetables group by name) FOR JSON PATH) as "Value"

但是，我收到了Error 156: Incorrect syntax near the keyword 'FOR'.

然后我尝试了以下方法：

SELECT 'FruitsAndVegCount' AS "Type", (SELECT count(id) as Counter, [Name] FROM Fruits group by name
UNION
SELECT count(id) as Counter, [Name] FROM Vegetables group by name FOR JSON PATH) as "Value"

但是，我收到了Error 1086: The FOR XML and FOR JSON clauses are invalid in views, inline functions, derived tables, and subqueries when they contain a set operator.

我一直试图让我的“联合化”查询采用格式 A。

更新 1：这是所需的输出

|---------------------|------------------------------------------------------------------------------------------------|
|        Type         |                                   Value                                                        |
|---------------------|------------------------------------------------------------------------------------------------|
|  FruitAndVegCount   | [{"Counter":2, "Name":"Apple"},{"Counter":3, "Name":"Orange"},{"Counter":7, "Name":"Tomato"}]  |
|---------------------|------------------------------------------------------------------------------------------------|

目标是只有一行，有 2 列（类型、值），其中类型是我指定的任何内容（即 FruitAndVegCount），值是由联合查询创建的 ResultSet 的 JSON。

Answer 1

如果我对问题的理解正确，可以选择以下语句：

SELECT 
   [Type] = 'FruitAndVegCount',
   [Value] = (
      SELECT Counter, Name
      FROM (
         SELECT count(id) as Counter, [Name] FROM Fruits group by name
         UNION ALL
         SELECT count(id) as Counter, [Name] FROM Vegetables group by name
      ) t
      FOR JSON PATH
   )

Answer 2

您可以使用两列 Type 和 Value 来完成，如下所示。像这样的

select 'FruitAndVegCount' as [Type],
        (select [Counter], [Name] 
         from (select count(id) as Counter, [Name] from #Fruits group by [name] 
               union all
               select count(id) as Counter, [Name] from #Vegetables group by [name]) u
          for json path) [Value];

输出

Type                Value
FruitAndVegCount    [{"Counter":2,"Name":"apple"},{"Counter":1,"Name":"pear"},{"Counter":2,"Name":"carrot"},{"Counter":1,"Name":"kale"},{"Counter":2,"Name":"lettuce"}]