Top 30 SQL Query Interview Questions You Must Practice In 2023

SELECT * FROM EmpPosition ORDER BY Salary DESC LIMIT N;

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Q15. Write a query to fetch details of employees with the address as “DELHI(DEL)”.

 
SELECT * FROM EmployeeInfo WHERE Address LIKE 'DELHI(DEL)%';

Q16. Write a query to fetch all employees who also hold the managerial position.

 
SELECT E.EmpFname, E.EmpLname, P.EmpPosition 
FROM EmployeeInfo E INNER JOIN EmployeePosition P ON 
E.EmpID = P.EmpID AND P.EmpPosition IN ('Manager');

Q17. Write a query to fetch the department-wise count of employees sorted by department’s count in ascending order.

 
SELECT Department, count(EmpID) AS EmpDeptCount 
FROM EmployeeInfo GROUP BY Department 
ORDER BY EmpDeptCount ASC;

Q18. Write a query to calculate the even and odd records from a table.

To retrieve the even records from a table, you have to use the MOD() function as follows:

 
SELECT EmpID FROM (SELECT rowno, EmpID from EmployeeInfo) WHERE MOD(rowno,2)=0;

Similarly, to retrieve the odd records from a table, you can write a query as follows:

 
SELECT EmpID FROM (SELECT rowno, EmpID from EmployeeInfo) WHERE MOD(rowno,2)=1;

Q19. Write a SQL query to retrieve employee details from EmployeeInfo table who have a date of joining in the EmployeePosition table.

 
SELECT * FROM EmployeeInfo E 
WHERE EXISTS 
(SELECT * FROM EmployeePosition P WHERE E.EmpId = P.EmpId);

Q20. Write a query to retrieve two minimum and maximum salaries from the EmployeePosition table.

To retrieve two minimum salaries, you can write a query as below:

 
SELECT DISTINCT Salary FROM EmployeePosition E1 
 WHERE 2 >= (SELECTCOUNT(DISTINCT Salary)FROM EmployeePosition E2 
  WHERE E1.Salary >= E2.Salary) ORDER BY E1.Salary DESC;

To retrieve two maximum salaries, you can write a query as below: 

 
SELECT DISTINCT Salary FROM EmployeePosition E1 
 WHERE 2 >= (SELECTCOUNT(DISTINCT Salary) FROM EmployeePosition E2 
  WHERE E1.Salary <= E2.Salary) ORDER BY E1.Salary DESC;

Q21. Write a query to find the Nth highest salary from the table without using TOP/limit keyword.

 
SELECT Salary 
FROM EmployeePosition E1 
WHERE N-1 = ( 
      SELECT COUNT( DISTINCT ( E2.Salary ) ) 
	  FROM EmployeePosition E2 
	  WHERE E2.Salary >  E1.Salary );

Q22. Write a query to retrieve duplicate records from a table.

 
SELECT EmpID, EmpFname, Department COUNT(*) 
FROM EmployeeInfo GROUP BY EmpID, EmpFname, Department 
HAVING COUNT(*) > 1;

Q23. Write a query to retrieve the list of employees working in the same department.

 
Select DISTINCT E.EmpID, E.EmpFname, E.Department 
FROM EmployeeInfo E, Employee E1 
WHERE E.Department = E1.Department AND E.EmpID != E1.EmpID;

Q24. Write a query to retrieve the last 3 records from the EmployeeInfo table.

SELECT * FROM EmployeeInfo WHERE 
EmpID <=3 UNION SELECT * FROM 
(SELECT * FROM EmployeeInfo E ORDER BY E.EmpID DESC) 
AS E1 WHERE E1.EmpID <=3;

Q25. Write a query to find the third-highest salary from the EmpPosition table.

SELECT TOP 1 salary
FROM(
SELECT TOP 3 salary
FROM employee_table
ORDER BY salary DESC) AS emp
ORDER BY salary ASC;

Q26. Write a query to display the first and the last record from the EmployeeInfo table.

To display the first record from the EmployeeInfo table, you can write a query as follows:

SELECT * FROM EmployeeInfo WHERE EmpID = (SELECT MIN(EmpID) FROM EmployeeInfo);

To display the last record from the EmployeeInfo table, you can write a query as follows:

SELECT * FROM EmployeeInfo WHERE EmpID = (SELECT MAX(EmpID) FROM EmployeeInfo);

Q27. Write a query to add email validation to your database

SELECT Email FROM EmployeeInfo WHERE NOT REGEXP_LIKE(Email, ‘[A-Z0-9._%+-]+@[A-Z0-9.-]+.[A-Z]{2,4}’, ‘i’);

Q28. Write a query to retrieve Departments who have less than 2 employees working in it.

SELECT DEPARTMENT, COUNT(EmpID) as 'EmpNo' FROM EmployeeInfo GROUP BY DEPARTMENT HAVING COUNT(EmpD) < 2;

Q29. Write a query to retrieve EmpPostion along with total salaries paid for each of them.

SELECT EmpPosition, SUM(Salary) from EmployeePosition GROUP BY EmpPosition;

Q30. Write a query to fetch 50% records from the EmployeeInfo table.

SELECT * 
FROM EmployeeInfo WHERE 
EmpID <= (SELECT COUNT(EmpID)/2 from EmployeeInfo);