选择SQL中缺少表达式

Question

我是SQL和子查询的新手，当我自己运行子查询时，将获得正确的数据输出。 但是，当我运行完整查询时，会收到错误消息

SELECT *第3行出现错误：ORA-00936：缺少表达式

这是我的代码：

SELECT 
MAX(
    SELECT 
    SUM(
        ALLOCATION.HourlyRate 
        * 
        ACTION.HrsWorked
        ) 
    FROM ALLOCATION 
    INNER JOIN ACTION 
    ON ((ACTION.ActId  = ALLOCATION.ActId) AND (ACTION.EmpId  = ALLOCATION.EmpId)) 
    GROUP BY (ALLOCATION.ActId)
)
FROM ALLOCATION
GROUP BY (ALLOCATION.ActId)

解：

   SELECT MAX(sum_total_pay)
FROM
(
    SELECT SUM(ALLOCATION.HourlyRate *  ACTION.HrsWorked) AS sum_total_pay
    FROM ALLOCATION 
    INNER JOIN ACTION 
    ON ((ACTION.ActId  = ALLOCATION.ActId) AND (ACTION.EmpId  = ALLOCATION.EmpId))
    GROUP BY (ALLOCATION.ActId)
);

Answer 1

您还需要两个括号：）

  SELECT MAX ( (  SELECT SUM (ALLOCATION.HourlyRate * ACTION.HrsWorked)
                    FROM ALLOCATION INNER JOIN ACTION ON (ACTION.ActId = ALLOCATION.ActId) AND (ACTION.EmpId = ALLOCATION.EmpId)
                GROUP BY (ALLOCATION.ActId)))
    FROM ALLOCATION
GROUP BY ALLOCATION.ActId

Select into MAX必须在括号内。

逻辑尚不清楚。 这样就可以得出每次活动的总收入：

  SELECT ALLOCATION.ActId, SUM (ALLOCATION.HourlyRate * ACTION.HrsWorked) total_pay
    FROM ALLOCATION b INNER JOIN ACTION ON ACTION.ActId = ALLOCATION.ActId AND ACTION.EmpId = ALLOCATION.EmpId
GROUP BY ALLOCATION.ActId

如果您想查看哪个活动支付的费用最高，请通过desc订购：

  SELECT *
    FROM (  SELECT ALLOCATION.ActId, SUM (ALLOCATION.HourlyRate * ACTION.HrsWorked) total_pay
              FROM ALLOCATION b INNER JOIN ACTION ON ACTION.ActId = ALLOCATION.ActId AND ACTION.EmpId = ALLOCATION.EmpId
          GROUP BY ALLOCATION.ActId)
ORDER BY total_pay DESC