Question { 9454 }

please can anyone answer this query

Table 1 has 2 columns: EmployeeId,Age
Table 2 has 2 columns: EmployeeId, Region
Write SQL to Find the region who has the oldest person

Answer

create table Employee(empId int,age int)
create table Area(empId int,Region varchar(20))

Use Inner Join

select e.empid,e.age,a.region from Employee e inner join
area a on e.empid=a.empid and e.age in
(select max(age) from Employee)

OR


select empid,region from area where empid in
(select empid from Employee where age
in(select max(age) from Employee))

Question { 7930 }

what is the difference between group and having
give an example with query and sample output

Answer

You Have two table person and friend
create table person(id int,pname varchar(20),gender varchar(3))
insert into person(id,pname,Gender)values(1,'krishna','m')
insert into person(id,pname,Gender)values(2,'Radha','m')
insert into person(id,pname,Gender)values(3,'Anamika','m')
insert into person(id,pname,Gender)values(4,'raj','m')
insert into person(id,pname,Gender)values(5,'suhani','m')
insert into person(id,pname,Gender)values(6,'ravi','m')

create table friend(id int,fid int)
insert into friend(id,fid)values(1,2)
insert into friend(id,fid)values(1,3)
insert into friend(id,fid)values(1,5)
insert into friend(id,fid)values(2,3)
insert into friend(id,fid)values(1,4)
insert into friend(id,fid)values(1,6)
insert into friend(id,fid)values(6,2)
insert into friend(id,fid)values(6,3)
insert into friend(id,fid)values(3,2)
insert into friend(id,fid)values(3,2)
insert into friend(id,fid)values(3,1)

find person who is male and having more than two female friend
Asnswer : -

select id,count(fid) as numberOfFemaleFriend from friend where fid in(select id from person where gender='f')
and id in (select id from person where gender='m' )
group by id having count(fid) >2

OR You can use Inner Join


select f.id,p.pname,count(f.fid) as numberOfFemaleFriend
from person p
inner join friend f
on p.id=f.id and p.gender='m' and f.fid in
(select id from person where gender='f')
group by f.id,p.pname having(count(f.fid)>2)

Question { 7930 }

what is the difference between group and having
give an example with query and sample output

Answer

You Have two table person and friend
create table person(id int,pname varchar(20),gender varchar(3))
insert into person(id,pname,Gender)values(1,'krishna','m')
insert into person(id,pname,Gender)values(2,'Radha','f')
insert into person(id,pname,Gender)values(3,'Anamika','f')
insert into person(id,pname,Gender)values(4,'raj','m')
insert into person(id,pname,Gender)values(5,'suhani','f')
insert into person(id,pname,Gender)values(6,'ravi','m')

create table friend(id int,fid int)
insert into friend(id,fid)values(1,2)
insert into friend(id,fid)values(1,3)
insert into friend(id,fid)values(1,5)
insert into friend(id,fid)values(2,3)
insert into friend(id,fid)values(1,4)
insert into friend(id,fid)values(1,6)
insert into friend(id,fid)values(6,2)
insert into friend(id,fid)values(6,3)
insert into friend(id,fid)values(3,2)
insert into friend(id,fid)values(3,2)
insert into friend(id,fid)values(3,1)

find person who is male and having more than two female friend
Asnswer : -

select id,count(fid) as numberOfFemaleFriend from friend where fid in(select id from person where gender='f')
and id in (select id from person where gender='m' )
group by id having count(fid) >2

OR You can use Inner Join


select f.id,p.pname,count(f.fid) as numberOfFemaleFriend
from person p
inner join friend f
on p.id=f.id and p.gender='m' and f.fid in
(select id from person where gender='f')
group by f.id,p.pname having(count(f.fid)>2)