In my previous articles I have given the way to write the complex sql queries. In this article I would like to focus on multiple ways to find second highest salary of employee in SQL. This is most asked interview question in SQL related interviews. I would like to throw light on multiple queries with its stepwise explanation.
Query to Find second highest Salary Of Employee one of the most commonly asked question in SQL interviews:
select distinct salary from Empoyee e1 where 2 = (select count(distinct salary) from Employee e2 where e1.salary <= e2.salary);
Explanation of Query for example :
1.Distinct keyword:–>The Distinct keyword is very useful keyword which will eliminate duplicates and fetches the Result.
2.Aliases–> Alias is nothing but the obfuscation technique to protect the real names of database fields
3.Count()–>Count() function is used to count the records in the table.
Step 1: So to understand the above query we will start with simple select statement. for Example,
Select * from Employee;
Here our intention is to fetch the record where salary is 2nd highest.
Step 2 :We will fetch the distinct Salary of employee and give the alias to it. For instance ,
Select distinct Salary from Employee e1;
Step 3 :We need to calculate 2nd highest salary.So we need to get the count of all distinct salaries. To illustrate this ,
Select count(distinct Salary) from Employee e2;
Step 4 :We actually need to calculate 2nd highest salary.So we will modify the Step 2 query and Step3 Query: Below is example,
Select distinct Salary from Employee e1 where 2=
Select count(distinct Salary) from Employee e2 where e1.salary<=e2.salary;
The above query will give us the 2nd highest salary of employee. Hope you will understand the logic behind fetching the second highest salary. There are other ways to find 2nd highest salary of employee using rank and dense_rank function.
Other ways to find 2nd highest salary:
SELECT max(e1.sal), e1.deptno FROM s_emp e1 WHERE sal < (SELECT max(sal) FROM s_emp e2 WHERE e2.deptno = e1.deptno) GROUP BY e1.deptno;
SELECT * FROM (SELECT S.*,DENSE_RANK() OVER (PARTITION BY DNO ORDER BY SALARY DESC) DR FROM SOURCE ) S WHERE S.DR=2;
Select Name From Employees Where Salary =
(Select Distinct Top(1) Salary from Employees where Salary Not In
(Select Dustinct Top(1) Salary from Employees Order By Salary Descending) Order by Salary Descending);
There are some other ways of calculating the second highest salary in different DBMS i.e. Oracle,Mysql,Postgresql:
Type 1 : Using correlated subquery:
SELECT name, salary FROM Employee e1 WHERE N-1 = (SELECT COUNT(DISTINCT salary) FROM Employee e2 WHERE e2.salary > e1.salary)SELECT name, salary FROM Employee e1 WHERE 2-1 = (SELECT COUNT(DISTINCT salary) FROM #Employee e2 WHERE e2.salary > e1.salary);
Using this method of finding out the second highest salary is slow because of the execution of inner query again and again.
Type 2: Microsoft SQL Server (Using Top Function)
SELECT TOP 1 salary FROM ( SELECT DISTINCT TOP N salary FROM Employee ORDER BY salary DESC ) AS temp ORDER BY salary;
Type3 : Mysql (using limit Clause)
SELECT salary FROM Employee ORDER BY salary DESC LIMIT 1,1;
Type 4: Oracle Function (using rownum function)
SELECT Salary FROM ( SELECT e.Salary, ROW_NUMBER() OVER (ORDER BY salary DESC) rn FROM Employee e ) WHERE rn = 2;
Type 5 : One of the website reader has suggested this solution Solution of Gautam Roy :
select * from OrderDetails a where a.Quantity < (select max(b.Quantity) from OrderDetails b) order by a.Quantity DESC limit 1;
Type 6 :However another Reader as given the below as to illustrate,
select max(sal) as maxsalary from salary where sal < ( select max(sal) as maxsalary from salary );
You can try this also for getting results easy accordingly,
Type 7 : Suggested by one of the Reader Selva Saleen for example :
select salary from (select rownum row_num,salary from (select * from EMPLOYEE E order by E.salary desc))where row_num=2;
Type 8 : Find Nth Highest Salary using Limit Keyword Suggested by Reader named Dinesh Singh for example :
Select name, salary from employee order by salary desc limit(1,n-1);
Type 9 :The next New Solution suggested by reader named Victor for example :
select distinct e2.salary
from (select A.Employee_num , A.salary , count(distinct B.salary) as salary_distinct_rank
from Employee A
where B.salary <= A.salary
group by A.Employee_num, A.salary ) e2
where e2.salary_distinct_rank = 2 ;
Type 10 : New Solution suggested by reader named Nikhita:
Select TOP 1 Salary from Employee where Salary<(Select max(Salary) from Employee);
These are above methods to calculate 2nd highest salary of Employee.If you like this article then don’t forget to share it.
I hope you like this article and the article is useful to find second highest salary in multiple ways. If you like this article or if you have any issues with the same kindly comment in comments section.