Question

      DECLARE

    v_department_name VARCHAR(50);
    v_department_manager VARCHAR(50);
    v_totalsalary NUMBER(5);

     BEGIN

  SELECT departments.department_name, concat(employees.first_name, employees.last_name), sum(employees.salary) 
  INTO v_department_name, v_department_manager, v_totalsalary 
  FROM employees LEFT JOIN departments ON employees.department_id =departments.department_id  WHERE  departments.department_id = 100;

   DBMS_OUTPUT.PUT_LINE ('Department Name is: ' || v_department_name || 'And    Department Manager is: ' || v_department_manager || 'Total Amount of Salary is: ' || v_totalsalary );

   END;

尝试显示department_name，部门经理（first_name，last_name）以及所赚取的工资总额时部门ID为100的员工，我明白了：

ORA-00937：不是单组组功能

导致该错误的原因是什么？

表员工（employee_id，first_name，last_name，department_id，manager_id，薪水）

表部门（department_id，department_name，manager_id，location_id）

Answer 1

ORA-00937：只是意味着您需要GROUP BY子句，并在该子句中重复不使用聚合函数（如SUM / MIN / MAX等）的select子句的每一列。 / p>

    SELECT
       departments.department_name
     , LISTAGG (employees.first_name || employees.last_name, '; ' )
           WITHIN GROUP (ORDER BY employees.last_name,employees.last_name) employee_names
     , SUM(employees.salary)
    FROM employees
    INNER JOIN departments ON employees.department_id = departments.department_id
    WHERE departments.department_id = 100
    GROUP BY
       departments.department_name
    ;

注意我正在使用LISTAGG（），但您不必使用它。如果您的3列需要是Department，Department Manager和（薪水总和），那么您需要从Manager的department表中选择正确的字段，然后在select和group by子句中包含该列。

Answer 2

WITH temp AS (
    SELECT d.department_name, concat(e.first_name, e.last_name) AS emp_name, 
        sum(e.salary) AS salary_sum
    FROM employees e LEFT JOIN departments d ON e.department_id =d.department_id  
    WHERE d.department_id = 100
    GROUP BY d.department_name, concat(e.first_name, e.last_name)  )
SELECT t.department_name, t.emp_name, t.salary_sum
INTO v_department_name, v_department_manager, v_totalsalary 
FROM temp

此查询使用公用表表达式将数据分组在一起，以使所有内容更加一致。您收到错误是因为您错过了原始查询中的GROUP BY d.department_name, concat(e.first_name, e.last_name)行。 SUM（）是一个聚合函数，只能与GROUP BY一起使用。

加入SQL查询会出现ORA-00937错误

2 个答案: