列出所有部门的部门名称和部门员工人数。如果部门没有员工，人数显示为0。正确的查询语句有_________。 A: SELECT dname,COUNT(ename) AS ecount FROM dept,emp WHERE emp.deptno(+)=dept.deptno GROUP BY dept.dname B: SELECT dname,(SELECT COUNT(*) AS ecount FROM emp WHERE emp.deptno=dept.deptno) FROM dept C: SELECT dname,COUNT(ename) AS ecount FROM dept LEFT JOIN emp ON emp.deptno=dept.deptno GROUP BY dept.dname D: SELECT dname,COUNT(*) AS ecount FROM dept LEFT JOIN emp ON emp.deptno=dept.deptno GROUP BY dept.dname

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2022-06-29

列出所有部门的部门名称和部门员工人数。如果部门没有员工，人数显示为0。正确的查询语句有_________。 A: SELECT dname,COUNT(ename) AS ecount FROM dept,emp WHERE emp.deptno(+)=dept.deptno GROUP BY dept.dname B: SELECT dname,(SELECT COUNT() AS ecount FROM emp WHERE emp.deptno=dept.deptno) FROM dept C: SELECT dname,COUNT(ename) AS ecount FROM dept LEFT JOIN emp ON emp.deptno=dept.deptno GROUP BY dept.dname D: SELECT dname,COUNT() AS ecount FROM dept LEFT JOIN emp ON emp.deptno=dept.deptno GROUP BY dept.dname

列出所有部门的部门名称和部门员工人数。如果部门没有员工，人数显示为0。正确的查询语句有_________。
A: SELECT dname,COUNT(ename) AS ecount
FROM dept,emp
WHERE emp.deptno(+)=dept.deptno
GROUP BY dept.dname
B: SELECT dname,(SELECT COUNT(*) AS ecount FROM emp WHERE emp.deptno=dept.deptno)
FROM dept
C: SELECT dname,COUNT(ename) AS ecount
FROM dept LEFT JOIN emp ON emp.deptno=dept.deptno
GROUP BY dept.dname
D: SELECT dname,COUNT(*) AS ecount
FROM dept LEFT JOIN emp ON emp.deptno=dept.deptno
GROUP BY dept.dname

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