1
這裏是我的表:每個部門有多少僱主工作?
SELECT * FROM DEPARTMENT;
DEPTNO DNAME LOC
---------- -------------------- --------------------
10 SWIFT WOLVER WOLVERHAMPTON
20 SWIFT BIR BIRMINGHAM
30 SWIFT MAN MANCHESTER
40 SWIFT LON LONDON
SELECT * FROM Employee;
EMPNO ENAME HIREDATE SAL DEPTNO
---------- ---------- ----------- ---------- ----------
1039 KING 17-NOV-1980 5000 10
1066 JONES 02-APR-1991 2975 20
1088 SCOTT 23-AUG-2016 3000 20
1276 ADAMS 26-SEP-2016 1100 20
1002 FORD 03-DEC-1991 3000 20
1169 SMITH 17-DEC-1990 800 20
1098 BLAKE 01-MAY-1981 2850 30
1099 ALLEN 20-FEB-1995 1600 30
1221 WARD 22-FEB-1994 1250 30
1454 MARTIN 28-SEP-1993 1250 30
1544 TURNER 08-SEP-1981 1500 30
1300 JAMES 03-DEC-1981 950 30
1482 CLARK 09-JUN-1989 2450 10
1134 MILLER 23-JAN-1985 1300 10
我有DEPTNO
(EMPLOYEE表)上DEPTNO
(部門表)的主鍵和外鍵。
我寫這個查詢應該列出多少僱主使用Group by
命令各個部門工作的事,但不起作用。當我試圖運行查詢時,出現COUNT
錯誤,但找不到具體的內容。誰能幫我這個?
SELECT DEPARTMENT.DNAME,COUNT(EMPLOYEE,DEPTNO) AS Numberofemployers FROM EMPLOYEE
LEFT JOIN DEPARTMENT
ON DEPARTMENT.DEPTNO = EMPLOYEE.DEPTNO
GROUP BY DEPARTMENTNAME;