Question

我想创建一个表NEW_DEPTS。我在DEPARTMENTS表中有DEPARTMENT_ID和DEPARTMENT_NAME。

            desc departments
            Name                            Null?    Type
            ------------------------------- -------- ----
            DEPARTMENT_ID                   NOT NULL NUMBER(4)
            DEPARTMENT_NAME                 NOT NULL VARCHAR2(30)
            MANAGER_ID                               NUMBER(6)
            LOCATION_ID                              NUMBER(4)

我的EMPLOYEES表包含：

            desc employees
            Name                            Null?    Type
            ------------------------------- -------- ----
            EMPLOYEE_ID                     NOT NULL NUMBER(6)
            FIRST_NAME                               VARCHAR2(20)
            LAST_NAME                       NOT NULL VARCHAR2(25)
            EMAIL                           NOT NULL VARCHAR2(25)
            PHONE_NUMBER                             VARCHAR2(20)
            HIRE_DATE                       NOT NULL DATE
            JOB_ID                          NOT NULL VARCHAR2(10)
            SALARY                                   NUMBER(8,2)
            COMMISSION_PCT                           NUMBER(2,2)
            MANAGER_ID                               NUMBER(6)
            DEPARTMENT_ID                            NUMBER(4)

现在，我想创建一个表NEW_DEPTS，其中应包含DEPARTMENT_ID和DEPARTMENT_NAME以及每个部门的总SALARY。每个部门都有一定数量的员工，因此，对于部门编号10,20,30等，应计算总薪资。

我的主要问题是：

           create table new_depts as
           select d.department_id,d.department_name,sum(e.salary) dept_sal
           from employees e,departments d
           where e.department_id = d.department_id;

我收到了错误：

           select d.department_id,d.department_name,sum(e.salary) dept_sal
              *
           ERROR at line 2:
           ORA-00937: not a single-group group function

所以，我用谷歌搜索了它。我发现在sum语句中不能使用sum，avg，max，min这样的组函数。我需要GROUP BY子句。所以，我想单独解决它。因此，我跳过了“创建表...”声明并写道：

           select distinct d.department_id,d.department_name,sum(e.salary) dept_sal
           from employees e,departments d
           where e.department_id = d.department_id
           group by department_id;

我收到了错误：

           group by department_id;
                  *
           ERROR at line 4:
           ORA-00911: invalid character

然后我写道：

           select d.department_id,d.department_name,sum(e.salary) dept_sal
           from employees e,departments d
           where e.department_id = d.department_id
           group by d.department_id;

我收到了错误：

           select d.department_id,d.department_name,sum(e.salary) dept_sal
                   *
           ERROR at line 1:
           ORA-00979: not a GROUP BY expression

然后我写道：

           select d.department_id,d.department_name,sum(e.salary) dept_sal
           from employees e,departments d
           where e.department_id = d.department_id
           group by department_id;

我收到了错误：

           group by department_id
                   *
           ERROR at line 4:
           ORA-00918: column ambiguously defined

我知道这是一个“加入”。但是没有得到如何放置GROUP BY子句以便我的GROUP FUNCTION可以正确运行。

Answer 1

您需要按聚合函数中的所有列进行分组，并且由于您已定义了表别名，因此必须在列中使用该别名。错误ORA-00918: column ambiguously defined是因为您有两列名为department_id的列，因此您必须指定department_id来自的表：

select d.department_id,
  d.department_name,
  sum(e.salary) dept_sal
from employees e
inner join departments d
  on e.department_id = d.department_id
group by d.department_id, d.department_name;

您会注意到我更改了查询以使用ANSI JOIN语法（INNER JOIN）。

错误：ORA-00937

1 个答案: