如何在 oracle 中使用子查询

Question

Hello I'm trying to solve this question with a subquery:

Select names, service number, jobs and salaries of people working in the same city as HAVET. (havet is a name)

And I have only two table the first one is the emp table with the column (noserv, name, job, salaries) and the second one is the SERV table with the column (noserv, nameserv, city)

I know that I have to use a subquery but I don't know how to do it.

Answer 1

Semi-pseudocode (CTE won't work, obviously).

with emp (noserv, name, job, salaries),
     serv (noserv, nameserv, city)
-- This is what you're looking for, I presume
select e.*
from emp e join serv s on e.noserv = s.noserv
where s.city = -- subquery returns city where HAVET lives
               (select s1.city 
                from serv s1 join emp e1 on e1.noserv = s1.noserv
                where e1.name = 'HAVET'
               );

Answer 2

Try this:

-- This is a normal query with a left join
select *
from emp e
left join s on e.noserv = s.noserv
where s.city = 

-- get Havet's city from the subquery.
(select s.city
from emp e
left join s on e.noserv = s.noserv
where e.name = 'HAVET') 

Answer 3

Try this one, change the column name according to your table and column names.

Select e.name,e.serviceNubmer,e.Job,e.salaries 
from emp e,serv s 
where 
e.noserv = s.noserv 
and s.city ='HAVET';