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how to check the 3rd max salary from an employee table? One
of the queries used is as follows:
select sal from emp a where 3=(select
count(distinct(sal)) from emp b
where a.sal<=b.sal).
Here in the sub query "select
count(distinct(sal)) from emp b
where a.sal<=b.sal" or
"select count(distinct(sal)) from emp b
where a.sal=b.sal" should reveal the same number of rows is
in't it? Can any one here please explain me how is this
query working perfectly.
However, there is another query to get the 3rd highest of
salaries of employees that logic I can understand. Pls find
the query below.
"select min(salary) from emp where salary in(select
distinct
top 3 salary from
emp order by salary desc)"
Please explain me how
"select sal from emp a where 3=(select
count(distinct(sal)) from emp b
where a.sal<=b.sal)" works
source:http://www.allinterview.com/showanswers/33264.html.
Thanks in advance
Regards,
Karthik.
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Answer Posted / gaurav
If you use "select count(distinct(sal)) from emp b
where a.sal=b.sal" It will always give output as 1. because for every salary in emp a, there will be one distinct sal in emp b.
So when we use a.sal <= b.sal, we are counting the number of people who have salary greater than or equal to your salary. So comparing it with 3 will give us 3rd maximum salary.
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