Complex SQL Queries Homework Help

COMPLEX QUERY IN SQL

1) To fetch ALTERNATE records from a table. (EVEN NUMBERED)

select * from emp

where rowid in (select decode( mod( rownum, 2), 0, rowid, null)

from emp);

2) To select ALTERNATE records from a table. (ODD NUMBERED)

select * from emp

where rowid in ( select decode ( mod ( rownum, 2 ), 0, null , rowed )

from emp);

3) Count MGR and their salary in emp table.

select count(MGR), count(sal)

from emp;

4) In emp table add comm+sal as total sal .

select ename,(sal+nvl(comm,0)) as totalsal

from emp;

5) Select any salary <3000 from emp table.

select * from emp

where sal > any (select sal from emp where sal<3000);

6) Select all salary <3000 from emp table.

select * from emp

where sal > all (select sal from emp where sal < 3000 );

7) Select all the employee group by deptno and sal in descending order.

select ename,deptno,sal from emp

order by deptno, sal

desc;

8) How can I create an empty table emp1 with same structure as emp?

Create table emp1 as select * from emp

where 1=2;

9) How to retrive record where sal between 1000 to 2000?

Select * from emp

where sal>=1000 And sal<2000

10) Find the 3rd MAX salary in the emp table.

select distinct sal from emp e1

where 3 = (select count (distinct sal )

from emp e2

where e1.sal <= e2.sal );

11) Find the 3rd MIN salary in the emp table.

select distinct sal from emp e1

where 3 = (select count(distinct sal)

from emp e2

where e1.sal >= e2.sal);

12) Select FIRST n records from a table.

select * from emp

where rownum <= &n;

13) Select LAST n records from a table

select * from emp

minus

select * from emp

where rownum <= (select count(*) - &n from emp);

14) List dept no., Dept name for all the departments in which there are no employees in the department.

select * from dept

where deptno not in (select deptno from emp);

alternate solution:

select * from dept a

where not exists (select * from emp b where a.deptno = b.deptno);

altertnate solution:

select empno,ename,b.deptno,dname from emp a, dept b

where a.deptno(+) = b.deptno and empno is null;

15) How to get 3 Max salaries ?

select distinct sal from emp a

where 3 >= (select count(distinct sal)

from emp b

where a.sal <= b.sal) order by a.sal

desc;

16) How to get 3 Min salaries ?

17) How to get nth max salaries ?

18) Select DISTINCT RECORDS from emp table.

19) How to delete duplicate rows in a table?

20) Count of number of employees in department wise.

21) Suppose there is annual salary information provided by emp table. How to fetch monthly salary of each and every employee?

22) Select all record from emp table where deptno =10 or 40.

23) Select all record from emp table where deptno=30 and sal>1500.

24) Select all record from emp where job not in SALESMAN or CLERK.

25) Select all record from emp where ename in 'BLAKE','SCOTT','KING'and'FORD'.

26) Select all records where ename starts with ‘S’ and its lenth is 6 char.

27) Select all records where ename may be any no of character but it should end with ‘R’.

28) Select all records where dept no of both emp and dept table matches.

29) If there are two tables emp1 and emp2, and both have common record. How can I fetch all the recods but common records only once?

30) How to fetch only common records from two tables emp and emp1?

(Select * from emp)

Intersect

(Select * from emp1)

31) How can I retrive all records of emp1 those should not present in emp2?

(Select * from emp)

Minus

(Select * from emp1)

32) Count the totalsa deptno wise where more than 2 employees exist.

SELECT deptno, sum(sal) As totalsal
FROM emp
GROUP BY deptno
HAVING COUNT(empno) > 2

TABLE : DEPARTMENT

TABLE : COURSE

TABLE : STUDENT

TABLE : STUDENT_GRADE

TABLE : TEACHER

TABLE : COURSE _INSTRUCTOR