“FIELDNAME”不是聚合函数的一部分-Access SQL

我试图从我的数据库中选择所有[Operation]，并获取每个[Operation]的数据。下面是我尝试使用的SQL代码

出现以下错误：

您试图执行的查询未将指定表达式“op”作为聚合函数的一部分

我的SQL语句：

SELECT [op] as [Operation], Sum(count) as [Number of Breakdowns], Sum(td) as [Sum of Time Down]
FROM
(
  SELECT [Operation] as op, Count(*) as count, Sum([Time Down]) as td
  FROM tblDailyDowntimeAssy
  WHERE [Type of Maintenance] = 'Breakdown'
UNION ALL
  SELECT [Operation] as op, Count(*) as count, Sum([Time Down]) as td
  FROM tblDailyDowntimeMach
  WHERE [Type of Maintenance] = 'Breakdown'
);

注:

如果我尝试只使用[Operation]字段而不将其重命名为op，则仍然会发生错误，但只是将“op”更改为“Operation”

  SELECT [Operation], Sum(count) as [Number of Breakdowns], Sum(td) as [Sum of Time Down]
FROM
(
  SELECT [Operation], Count(*) as count, Sum([Time Down]) as td
  FROM tblDailyDowntimeAssy
  WHERE [Type of Maintenance] = 'Breakdown'
  group by [Operation]
UNION ALL
  SELECT [Operation], Count(*) as count, Sum([Time Down]) as td
  FROM tblDailyDowntimeMach
  WHERE [Type of Maintenance] = 'Breakdown'
  group by [Operation]
)
group by Operation;

---

使用聚合函数时，需要在查询中添加GROUP BY子句。

需要在查询中添加GROUP BY子句

select ..... from tbl_name
group by ....

---

然后将该字段添加到错误中提到的group by子句中

编辑得好，我正要发布你需要添加该字段才能使其正确，哈哈。非常感谢，这节省了我很多时间。为什么我需要添加group by才能正常工作？您需要group by，因为您正在执行一个需要多行的聚合查询，每个操作一个。@GordonLinoff如果我理解正确的话-我需要group by子句，因为我正在搜索多个聚合查询，查询需要知道它通过什么将数据组合在一起。在本例中，它结合了我的[Operation]字段周围的数据。