Consider the following query:SELECT dname, ename FROM dept d, emp e Where d.deptno=c.deptno ORDER BY dname, ename;What type of join is shown?() A: Self-join B: Equijoin C: Outerjoin D: Non-equijoin

2022-05-31

Consider the following query:SELECT dname, ename FROM dept d, emp e Where d.deptno=c.deptno ORDER BY dname, ename;What type of join is shown?() A: Self-join B: Equijoin C: Outerjoin D: Non-equijoin

Consider the following query:SELECT dname, ename FROM dept d, emp e Where d.deptno=c.deptno ORDER BY dname, ename;What type of join is shown?()
A: Self-join
B: Equijoin
C: Outerjoin
D: Non-equijoin

答案：

B

举一反三

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
以下语句不正确的是( ) A: select * from emp; B: select ename,hiredate,sal from emp; C: select * from emp order deptno; D: select * from where deptno=1
以下语句不正确的是( ) A: select * from emp B: select ename,hiredate,sal from emp C: select * from emp order deptno D: select * from where deptno=1 and sal<300
智慧职教: 表结构如下：dept（deptno,dname）,emp(empno,ename,job,hiredate,sal，deptno)。创建视图查询系部名称、教师姓名，职位，工资信息。
现有关系模式: EMP(empno,ename,mgr,sal,workday) 以及DEPT(deptno,dname,loc) ,以下视图中不可能更新的为________

内容

0
查询部门20的员工数量,每个月的工资总和及平均工资( ) A: SELECT sum(nvl(sal,0)),avg(nvl(sal,0)) from emp B: SELECT ename,sum(nvl(sal,0)),avg(nvl(sal,0)) from emp where deptno =20 group by deptno C: SELECT ename,count(empno),sum(nvl(sal,0)),avg(nvl(sal,0)) from emp where deptno =20 group by deptno D: SELECT count(empno),sum(nvl(sal,0)),avg(nvl(sal,0)) from emp where deptno =20 group by deptno
1
统计每个部门中人数的语句是？ A: select count(id) from emp order by deptno; B: select sum(id) from emp order by deptno; C: select count(id) from emp group by deptno; D: select sum(id) from emp group by deptno;
2
列出所有员工的姓名、部门名称和工资。正确的SQL语句有________。 A: SELECT a.ename ,(SELECT b.dname FROM dept b) AS dname ,sal FROM emp a B: SELECT a.ename ,(SELECT b.dname FROM dept b WHERE b.deptno=a.deptno) AS dname ,sal FROM emp a; C: SELECT a.ename,b.dname,sal FROM emp a,dept D: SELECT a.ename,b.dname,sal FROM emp a,dept b WHERE a.deptno=b.deptno
3
以下语句正确的是() A: select sal+1 from emp; B: select sal*10,sal*deptno from emp; C: 不能使用运算符号 D: select sal*10,deptno*10 from emp;
4
以下哪个查询操作能够实现将员工的参加工作日期按如下格式显示：月份/年份。 A: select ename,hiredate,to_char(hiredate,'HH/RR') from emp; B: select ename,hiredate,to_char(hiredate,'MM/RR') from emp; C: select ename,hiredate,to_char(hiredate,'MON') from emp; D: select ename,hiredate,to_char(hiredate,'DD/YY') from emp;