我在回答这个问题时遇到了麻烦，我似乎无法正确计数 在每个部门上，只选择最高的部门并排除 “达拉斯”
这就是问题
“编写一条SQL语句，显示所有部门的名称和位置 (位于达拉斯的部门除外)数量最多的 雇员。
您不能在 SQL 语句中使用连接操作(例如，... FROM Department, 员工 WHERE …，部门 INNER JOIN 员工 ON …)。”
DEPARTMENT_ID DEPARTMENT_NAME LOCATION
------------- -------------------- --------------------
10 ACCOUNTING NEW YORK
20 RESEARCH DALLAS
30 SALES CHICAGO
40 IT DALLAS
50 EXECUTIVE NEW YORK
60 MARKETING CHICAGO
6 rows selected
EMPLOYEE_ID EMPLOYEE_NAME JOB_TITLE SUPERVISOR_ID HIRE_DATE SALARY COMMISSION DEPARTMENT_ID
----------- -------------------- -------------------------------------------------- ------------- --------- ---------- ---------- -------------
7839 KING PRESIDENT 20-NOV-01 5000 50
7596 JOST VICE PRESIDENT 7839 04-MAY-01 4500 50
7603 CLARK VICE PRESIDENT 7839 12-JUN-01 4000 50
7566 JONES CHIEF ACCOUNTANT 7596 05-APR-01 3000 10
7886 STEEL PUBLIC ACCOUNTANT 7566 08-MAR-03 2500 10
7610 WILSON BUSINESS ANALYST 7596 03-DEC-01 3000 20
7999 WOLFE TEST ANALYST 7610 15-FEB-02 2500 20
7944 LEE REPORTING ANALYST 7610 04-SEP-06 2400 20
7900 FISHER SALES EXECUTIVE 7603 06-DEC-01 3000 500 30
7921 JACKSON SALES REPRESENTATIVE 7900 25-FEB-05 2500 400 30
7952 LANCASTER SALES CONSULTANT 7900 06-DEC-06 2000 150 30
7910 SMITH DATABASE ADMINISTRATOR 7596 20-DEC-01 2900 40
7788 SCOTT PROGRAMMER 7910 15-JAN-03 2500 40
7876 ADAMS PROGRAMMER 7910 15-JAN-03 2000 40
7934 MILLER PROGRAMMER 7876 25-JAN-02 1000 40
8000 BREWSTER TBA 22-AUG-13 2500
8100 PHILLIPS TBA 7839 21-AUG-13 2800
7400 SMITH VICE PRESIDENT 7839 16-FEB-01 4300 50
7700 ANDRUS PUBLIC ACCOUNTANT 7566 18-FEB-02 2500 10
7601 SAMPSON PROGRAMMER 7910 09-JAN-01 2500 40
7588 DODSON TEST ANALYST 7610 02-AUG-08 2500 20
7888 SANDY SALES CONSULTANT 7900 05-AUG-04 2500 30
22 rows selected
SELECT DEPARTMENT_NAME,
location,
count(*)
FROM DEPARTMENT
WHERE department_id IN ( SELECT department_id
FROM department
WHERE UPPER(location) <> 'DALLAS'
)
group by department_NAME, location
ORDER BY location;
DEPARTMENT_NAME LOCATION COUNT(*)
-------------------- -------------------- ----------
MARKETING CHICAGO 1
SALES CHICAGO 1
ACCOUNTING NEW YORK 1
EXECUTIVE NEW YORK 1
最佳答案
如果您无法使用联接，您可以尝试使用子查询
SELECT *
FROM (SELECT d.department_name,
d.location,
(SELECT COUNT(employee_id)
FROM employee e
WHERE e.department_id = d.department_id) no_employees
FROM department d
WHERE d.location <> 'DALLAS'
) t
WHERE no_employees = (SELECT COUNT(employee_id)
FROM employee
WHERE department_id IN (SELECT DISTINCT department_id
FROM department
WHERE location <> 'DALLAS')
GROUP BY department_id
ORDER BY 1 DESC
LIMIT 1)
结果
department_name location no_employees
SALES CHICAGO 4
EXECUTIVE NEW YORK 4
关于mysql - 如何在不使用JOIN和统计员工数量的情况下显示数据？，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/46289161/