Question

尝试显示订单数量最多的工作人员的详细信息，在oracle中有一个错误，指出群组功能嵌套太深＆＃39;。

SELECT c.Staff_No, s.First_name, s.Last_Name, max(COUNT(*)) AS "Number Of Orders"
  FROM Cust_Order c, 
       Staff s   
 WHERE c.Staff_No = s.Staff_No
 GROUP 
    BY c.Staff_No, s.First_name, s.Last_Name
HAVING MAX(COUNT(*)) > (SELECT MAX((COUNT(*))
                          FROM Cust_Order c, Staff s 
                         WHERE c.Staff_No = s.Staff_No);

Answer 1

相反，使用分析函数：

SELECT Staff_No, First_name, Last_Name, "Number Of Orders"
FROM (SELECT c.Staff_No, s.First_name, s.Last_Name, COUNT(*) AS "Number Of Orders",
             max(count(*)) over () as maxcount
      FROM Cust_Order c JOIN
           Staff s                                                                                                                                                                                                                                                                                                                          
           ON c.Staff_No = s.Staff_No
      GROUP BY c.Staff_No, s.First_name, s.Last_Name
     ) cs
WHERE "Number Of Orders" = maxcount;

这也应该有更好的表现。

在Having子句中按功能分组，子查询和嵌套分组

1 个答案: