用SQL完成以下问题列表：
1．列出至少有一个员工的所有部门。 2．列出薪金比“SMITH”多的所有员工。 3．列出所有员工的姓名及其直接上级的姓名。 4．列出受雇日期早于其直接上级的所有员工。 5．列出部门名称和这些部门的员工信息，同时列出那些没有员工的部门 6．列出所有“CLERK”（办事员）的姓名及其部门名称。 7．列出最低薪金大于1500的各种工作。 8．列出在部门“SALES”（销售部）工作的员工的姓名，假定不知道销售部的部门编号。 9．列出薪金高于公司平均薪金的所有员工。 10．列出与“SCOTT”从事相同工作的所有员工。 11．列出薪金等于部门30中员工的薪金的所有员工的姓名和薪金。 12．列出薪金高于在部门30工作的所有员工的薪金的员工姓名和薪金。 13．列出在每个部门工作的员工数量、平均工资和平均服务期限。 14．列出所有员工的姓名、部门名称和工资。 15．列出所有部门的详细信息和部门人数。 16．列出各种工作的最低工资。 17．列出各个部门的MANAGER（经理）的最低薪金。 18．列出所有员工的年工资,按年薪从低到高排序。
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各答案如下，欢迎大家给出不出的解答方式。
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--------1．列出至少有一个员工的所有部门。--------- SQL> select dname from dept where deptno in(select deptno fromemp);
DNAME -------------- RESEARCH
SALES
ACCOUNTING --------或-------- SQL> select dname from dept where deptno in(select deptno from emp group by deptno having count(deptno) >=1);
DNAME -------------- ACCOUNTING
RESEARCH
SALES --------2．列出薪金比“SMITH”多的所有员工。---------- SQL> select * from emp where sal > (select sal from emp where ename = 'SMITH');
EMPNO ENAME JOB MGR HIREDATE SAL COMM DEPTNO ----- ---------- --------- ----- ----------- --------- --------- ------ 7499 ALLEN SALESMAN 7698 1981-2-20 1600.00 300.00 30 7521 WARD SALESMAN 7698 1981-2-22 1250.00 500.00 30 7566 JONES MANAGER 7839 1981-4-2 2975.00 20 7654 MARTIN SALESMAN 7698 1981-9-28 1250.00 1400.00 30 7698 BLAKE MANAGER 7839 1981-5-1 2850.00 30 7782 CLARK MANAGER 7839 1981-6-9 2450.00 10 7788 SCOTT ANALYST 7566 1987-4-19 4000.00 20 7839 KING PRESIDENT 1981-11-17 5000.00 10 7844 TURNER SALESMAN 7698 1981-9-8 1500.00 0.00 30 7876 ADAMS CLERK 7788 1987-5-23 1100.00 20 7900 JAMES CLERK 7698 1981-12-3 950.00 30 7902 FORD ANALYST 7566 1981-12-3 3000.00 20 7934 MILLER CLERK 7782 1982-1-23 1300.00 10 102 EricHu Developer 1455 2011-5-26 1 5500.00 14.00 10 104 huyong PM 1455 2011-5-26 1 5500.00 14.00 10 105 WANGJING Developer 1455 2011-5-26 1 5500.00 14.00 10 16rows selected --------3．列出所有员工的姓名及其直接上级的姓名。---------- SQL> select a.ename,(select ename from emp b where b.empno=a.mgr) as boss_name fromemp a;
ENAME BOSS_NAME ---------- ---------- SMITH FORD
ALLEN BLAKE
WARD BLAKE
JONES KING
MARTIN BLAKE
BLAKE KING
CLARK KING
SCOTT JONES
KING
TURNER BLAKE
ADAMS SCOTT
JAMES BLAKE
FORD JONES
MILLER CLARK
EricHu
huyong
WANGJING 17rows selected --------4．列出受雇日期早于其直接上级的所有员工。---------- SQL> select a.ename from emp a where a.hiredate<(select hiredate from emp b where b.empno=a.mgr);
ENAME ---------- SMITH
ALLEN
WARD
JONES
BLAKE
CLARK 6rows selected --------5．列出部门名称和这些部门的员工信息，同时列出那些没有员工的部门---------- SQL> select a.dname,b.empno,b.ename,b.job,b.mgr,b.hiredate,b.sal,b.deptno
2 from dept a left join emp b on a.deptno=b.deptno;
DNAME EMPNO ENAME JOB MGR HIREDATE SAL DEPTNO -------------- ----- ---------- --------- ----- ----------- --------- ------ RESEARCH 7369 SMITH CLERK 7902 1980-12-17 800.00 20 SALES7499 ALLEN SALESMAN 7698 1981-2-20 1600.00 30 SALES7521 WARD SALESMAN 7698 1981-2-22 1250.00 30 RESEARCH7566 JONES MANAGER 7839 1981-4-2 2975.00 20 SALES7654 MARTIN SALESMAN 7698 1981-9-28 1250.00 30 SALES7698 BLAKE MANAGER 7839 1981-5-1 2850.00 30 ACCOUNTING7782 CLARK MANAGER 7839 1981-6-9 2450.00 10 RESEARCH7788 SCOTT ANALYST 7566 1987-4-19 4000.00 20 ACCOUNTING7839 KING PRESIDENT 1981-11-17 5000.00 10 SALES7844 TURNER SALESMAN 7698 1981-9-8 1500.00 30 RESEARCH7876 ADAMS CLERK 7788 1987-5-23 1100.00 20 SALES7900 JAMES CLERK 7698 1981-12-3 950.00 30 RESEARCH7902 FORD ANALYST 7566 1981-12-3 3000.00 20 ACCOUNTING7934 MILLER CLERK 7782 1982-1-23 1300.00 10 ACCOUNTING102 EricHu Developer 1455 2011-5-26 1 5500.00 10 ACCOUNTING104 huyong PM 1455 2011-5-26 1 5500.00 10 ACCOUNTING105 WANGJING Developer 1455 2011-5-26 1 5500.00 10 50abc
OPERATIONS
Developer 20rows selected --------6．列出所有“CLERK”（办事员）的姓名及其部门名称。---------- SQL> select a.ename,b.dname from emp a join dept b on a.deptno=b.deptno and a.job='CLERK';
ENAME DNAME ---------- -------------- SMITH RESEARCH
ADAMS RESEARCH
JAMES SALES
MILLER ACCOUNTING --------7．列出最低薪金大于1500的各种工作。---------- SQL> select distinct job as HighSalJob from emp group by job having min(sal)>1500;
HIGHSALJOB ---------- ANALYST
Developer
MANAGER
PM
PRESIDENT --------8．列出在部门“SALES”（销售部）工作的员工的姓名，假定不知道销售部的部门编号。---------- SQL> select ename from emp where deptno=(select deptno from dept where dname='SALES');
ENAME ---------- ALLEN
WARD
MARTIN
BLAKE
TURNER
JAMES 6rows selected --------9．列出薪金高于公司平均薪金的所有员工。---------- SQL> select ename from emp where sal>(select avg(sal) fromemp);
ENAME ---------- JONES
BLAKE
SCOTT
KING
FORD
EricHu
huyong
WANGJING 8rows selected --------10．列出与“SCOTT”从事相同工作的所有员工。-------- SQL> select ename from emp where job=(select job from emp where ename='SCOTT');
ENAME ---------- SCOTT
FORD --------11．列出薪金等于部门30中员工的薪金的所有员工的姓名和薪金。--------- SQL> select a.ename,a.sal from emp a where a.sal in (select b.sal
2 from emp b where b.deptno=30) and a.deptno<>30;
ENAME SAL ---------- --------- --------12．列出薪金高于在部门30工作的所有员工的薪金的员工姓名和薪金。--------- SQL> select ename,sal from emp where sal>(select max(sal) from emp where deptno=30);
ENAME SAL ---------- --------- JONES 2975.00 SCOTT4000.00 KING5000.00 FORD3000.00 EricHu5500.00 huyong5500.00 WANGJING5500.00 7rows selected --------13．列出在每个部门工作的员工数量、平均工资和平均服务期限。--------- SQL> select (select b.dname from dept b where a.deptno=b.deptno) as deptname ,count(deptno) as deptcount,avg(sal) as deptavgsal
2 from emp a group bydeptno;
DEPTNAME DEPTCOUNT DEPTAVGSAL -------------- ---------- ---------- ACCOUNTING 6 4208.33333 RESEARCH5 2375 SALES6 1566.66666 --------14．列出所有员工的姓名、部门名称和工资。--------- SQL> select a.ename,(select b.dname from dept b where b.deptno=a.deptno) as deptname,sal fromemp a;
ENAME DEPTNAME SAL ---------- -------------- --------- SMITH RESEARCH 800.00 ALLEN SALES1600.00 WARD SALES1250.00 JONES RESEARCH2975.00 MARTIN SALES1250.00 BLAKE SALES2850.00 CLARK ACCOUNTING2450.00 SCOTT RESEARCH4000.00 KING ACCOUNTING5000.00 TURNER SALES1500.00 ADAMS RESEARCH1100.00 JAMES SALES950.00 FORD RESEARCH3000.00 MILLER ACCOUNTING1300.00 EricHu ACCOUNTING5500.00 huyong ACCOUNTING5500.00 WANGJING ACCOUNTING5500.00 17rows selected --------15．列出所有部门的详细信息和部门人数。--------- SQL> select a.deptno,a.dname,a.loc,(select count(deptno) from emp b where b.deptno=a.deptno group by b.deptno) as deptcount fromdept a;
DEPTNO DNAME LOC DEPTCOUNT ------ -------------- ------------- ---------- 10 ACCOUNTING NEW YORK 6 20 RESEARCH DALLAS 5 30 SALES CHICAGO 6 40 OPERATIONS BOSTON
50 50abc 50def
60Developer HaiKou 6rows selected --------16．列出各种工作的最低工资。--------- SQL> select job,avg(sal) from emp group by job;
JOB AVG(SAL) --------- ---------- ANALYST 3500 CLERK1037.5 Developer5500 MANAGER2758.33333 PM5500 PRESIDENT5000 SALESMAN1400 7rows selected --------17．列出各个部门的MANAGER（经理）的最低薪金。-------- SQL> select deptno,min(sal) from emp where job='MANAGER' group by deptno;
DEPTNO MIN(SAL) ------ ---------- 10 2450 20 2975 30 2850 --------18．列出所有员工的年工资,按年薪从低到高排序。--------- SQL> select ename,(sal+nvl(comm,0))*12 as salpersal from emp order bysalpersal;
ENAME SALPERSAL ---------- ---------- SMITH 9600 JAMES11400 ADAMS13200 MILLER15600 TURNER18000 WARD21000 ALLEN22800 CLARK29400 MARTIN31800 BLAKE34200 JONES35700 FORD36000 SCOTT48000 KING60000 EricHu66168 huyong66168 WANGJING66168 17 rows selected
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