Finden Sie die Anzahl der Mitarbeiter in jeder Abteilung - SQL Oracle

Question

Ich habe zwei Tabellen Emp und und ich versuche zu zeigen, wie viele Leute in jeder Abteilung zusammen mit ihren Abteilungsnamen arbeiten, aber ich kann es nicht zum Laufen bringen. Ich habe dies select count(ename) as count from emp group by deptno; versucht, aber die Ausgabe ich immer bin, ist dies:

COUNT 
---------- 
    6 
    5 
    3 

Aber ich möchte auch für jede dieser Abteilungen, die Namen zeigen. Hier sind meine Tabellen:

Empt:

CREATE TABLE EMP 
     (EMPNO NUMBER(4) NOT NULL, 
     ENAME VARCHAR2(10), 
     JOB VARCHAR2(9), 
     MGR NUMBER(4), 
     HIREDATE DATE, 
     SAL NUMBER(7, 2), 
     COMM NUMBER(7, 2), 
     DEPTNO NUMBER(2)); 

INSERT INTO EMP VALUES 
     (7369, 'SMITH', 'CLERK',  7902, 
     TO_DATE('17-DEC-1980', 'DD-MON-YYYY'), 800, NULL, 20); 
INSERT INTO EMP VALUES 
     (7499, 'ALLEN', 'SALESMAN', 7698, 
     TO_DATE('20-FEB-1981', 'DD-MON-YYYY'), 1600, 300, 30); 
INSERT INTO EMP VALUES 
     (7521, 'WARD', 'SALESMAN', 7698, 
     TO_DATE('22-FEB-1981', 'DD-MON-YYYY'), 1250, 500, 30); 
INSERT INTO EMP VALUES 
     (7566, 'JONES', 'MANAGER', 7839, 
     TO_DATE('2-APR-1981', 'DD-MON-YYYY'), 2975, NULL, 20); 
INSERT INTO EMP VALUES 
     (7654, 'MARTIN', 'SALESMAN', 7698, 
     TO_DATE('28-SEP-1981', 'DD-MON-YYYY'), 1250, 1400, 30); 
INSERT INTO EMP VALUES 
     (7698, 'BLAKE', 'MANAGER', 7839, 
     TO_DATE('1-MAY-1981', 'DD-MON-YYYY'), 2850, NULL, 30); 
INSERT INTO EMP VALUES 
     (7782, 'CLARK', 'MANAGER', 7839, 
     TO_DATE('9-JUN-1981', 'DD-MON-YYYY'), 2450, NULL, 10); 
INSERT INTO EMP VALUES 
     (7788, 'SCOTT', 'ANALYST', 7566, 
     TO_DATE('09-DEC-1982', 'DD-MON-YYYY'), 3000, NULL, 20); 
INSERT INTO EMP VALUES 
     (7839, 'KING', 'PRESIDENT', NULL, 
     TO_DATE('17-NOV-1981', 'DD-MON-YYYY'), 5000, NULL, 10); 
INSERT INTO EMP VALUES 
     (7844, 'TURNER', 'SALESMAN', 7698, 
     TO_DATE('8-SEP-1981', 'DD-MON-YYYY'), 1500, 0, 30); 
INSERT INTO EMP VALUES 
     (7876, 'ADAMS', 'CLERK',  7788, 
     TO_DATE('12-JAN-1983', 'DD-MON-YYYY'), 1100, NULL, 20); 
INSERT INTO EMP VALUES 
     (7900, 'JAMES', 'CLERK',  7698, 
     TO_DATE('3-DEC-1981', 'DD-MON-YYYY'), 950, NULL, 30); 
INSERT INTO EMP VALUES 
     (7902, 'FORD', 'ANALYST', 7566, 
     TO_DATE('3-DEC-1981', 'DD-MON-YYYY'), 3000, NULL, 20); 
INSERT INTO EMP VALUES 
     (7934, 'MILLER', 'CLERK',  7782, 
     TO_DATE('23-JAN-1982', 'DD-MON-YYYY'), 1300, NULL, 10); 

Dept:

CREATE TABLE DEPT 
     (DEPTNO NUMBER(2), 
     DNAME VARCHAR2(14), 
     LOC VARCHAR2(13)); 

INSERT INTO DEPT VALUES (10, 'ACCOUNTING', 'NEW YORK'); 
INSERT INTO DEPT VALUES (20, 'RESEARCH', 'DALLAS'); 
INSERT INTO DEPT VALUES (30, 'SALES',  'CHICAGO'); 
INSERT INTO DEPT VALUES (40, 'OPERATIONS', 'BOSTON'); 

Answer 1

Bitte versuchen:

select count(*) as count,dept.DNAME 
from emp 
inner join dept on emp.DEPTNO = dept.DEPTNO 
group by dept.DNAME 

Answer 2

select count(e.empno), d.deptno, d.dname 
from emp e, dep d 
where e.DEPTNO = d.DEPTNO 
group by d.deptno, d.dname; 

Answer 3

SELECT d.DEPTNO 
    , d.dname 
    , COUNT(e.ename) AS count 
FROM emp e 
     INNER JOIN dept d ON e.DEPTNO = d.deptno 
GROUP BY d.deptno 
     , d.dname;