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我想创建一个表 NEW_DEPTS。我有 DEPARTMENT_ID 和 DEPARTMENT_NAME，它们位于 DEPARTMENTS 表中。

            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 NEW_DEPTS 表，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，应计算总工资。

我的主要查询是：

           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;

我收到一个错误：

           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google了一下。我发现像 sum、avg、max、min 这样的组函数不能在 select 语句中使用。我需要 GROUP BY 子句。所以，我想单独解决它。因此，我跳过了“create table ...”语句并写道：

           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;

我得到错误：

           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;

我得到错误：

           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;

我得到错误：

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

I know that its a "join". But not getting how should I place GROUP BY clause so that my GROUP FUNCTION may run correctly.

4

1 回答 1

1

You need to group by all columns not in an aggregate function and since you have defined a table alias you must use that in your columns. The error ORA-00918: column ambiguously defined is because you have two columns named department_id so you must specify the table the department_id is from:

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;

You will notice that I altered the query to use ANSI JOIN syntax (INNER JOIN).

于 2013-03-30T04:29:08.103 回答