二三四五六章作业

–chapter 2

–1

–SELECT * FROM emp

–SELECT * FROM dept

–SELECT * FROM salgrade

–2

/*DESC emp

DESC dept

DESC salgrade*/

–3

–SELECT DISTINCT deptno ,job FROM emp

–chapter 3

–1

/*SELECT ename , hiredate ,job FROM emp

WHERE hiredate>’09-7月-82’

AND job<>’SALESMAN’*/

–2

/*

SELECT ename FROM emp

WHERE ename LIKE ‘__A%’*/

–3

/*SELECT ename ,deptno FROM emp

WHERE deptno NOT IN (10,20)*/

–4

/SELECT FROM emp

WHERE deptno IN (30)

ORDER BY sal DESC , ename ASC*/

–5

/*SELECT ename FROM emp

WHERE mgr IS NULL*/

–6

/*SELECT ename ,sal ,deptno FROM emp

WHERE sal>4500

AND deptno IN (10,20)*/

–chapter 4

–1

–SELECT months_between(SYSDATE,’01-1月-00’) MONTHS , ROUND(SYSDATE-TO_DATE(‘2000-1月-1’, ‘YYYY-month-dd’))/7 WEEKS FROM dual

–2

–SELECT * FROM emp

–WHERE SUBSTR(ename,3,1)=’A’

–WHERE INSTR(ename,’A’,3,1)=3

–3

–SELECT TRIM (‘h’ FROM ‘Hello’) FROM dual

–SELECT TRIM (’ ’ FROM ’ Hello ‘) FROM dual

–SELECT TRIM (‘b’ FROM ‘bllb’) FROM dual

–SELECT TRIM (’ ’ FROM ’ hello ‘) FROM dual

–4

–SELECT to_char(sal,’999,999.00L’) FROM emp

–5

–SELECT ename ,NVL(to_char(mgr),’No manager’) FROM emp –参数类型匹配

–WHERE mgr IS NULL

–6

–SELECT to_char(hiredate,’mon/rr’) “mm/rr” FROM emp

–7

– SELECT ename ,sal ,DECODE(TRUNC(sal/1000),

– 0 , 0,

– 1 , sal*.1,

– 2 , sal*.15,

– sal*.2) TAX FROM emp

–8

–SELECT ename ,LPAD(sal,15,’$’) sal FROM emp

–chapter 5

–1

/*SELECT worker.ename 员工姓名,dname 部门名称,manager.ename 直接上级名称 FROM emp worker,emp manager ,dept d

WHERE worker.deptno=d.deptno

AND manager.deptno=d.deptno

AND manager.empno=worker.mgr

AND worker.ename =’SMITH’ */

–2

/*SELECT ename ,dname ,sal ,grade FROM emp e,dept d ,salgrade g

WHERE grade>4

AND e.deptno =d.deptno

AND e.sal BETWEEN g.losal AND g.hisal*/

–3

/*SELECT e.ename 员工,m.ename 经理 FROM emp e,emp m

WHERE m.ename IN (‘KING’,’FORD’)

AND e.mgr=m.empno*/

–4

/*SELECT e.ename ,e.hiredate ,m.ename FROM emp e,emp m

WHERE e.mgr=m.empno

AND e.hiredate