Top 20 SQL Query Interview Questions You Must Practice In 2020 (Latest)

 20 most popular SQL Query Interview Questions and Answers:

SQL or Structured Query Language is a standard language for dealing with relational databases. it is very important for us to understand how to use queries to retrieve the required data.I will discuss a few queries which you must practice to become a Database Administrator.I will be discussing the top SQL queries which could be asked in your interviews.   

Q1. Write a query to create a new table which consists of data and structure copied from the other table.

Ans:-  SELECT * INTO NewTable FROM EmployeeInfo WHERE 1 = 0;

Q2. Write a query to fetch the number of employees working in the department ‘HR’.

Ans:- SELECT COUNT(*) FROM EmployeeInfo WHERE Department = 'HR';

Q3. Write a query to get the current date.

Ans:- SELECT GETDATE();

Q4. Write a query to find the names of employees that begin with ‘S’.

Ans:- SELECT * FROM EmployeeInfo WHERE EmpFname ='S%';

Q5. Write a query to fetch top N records.

Ans:- SELECT TOP N * FROM EmployeePosition ORDER BY Salary DESC;

Q6. Write a query to retrieve the EmpFname and EmpLname in a single column as “FullName”. The first name and the last name must be separated with space.

Ans:- SELECT CONCAT(EmpFname, ' ', EmpLname) AS 'FullName' FROM EmployeeInfo;

Q7. Write a query to fetch the EmpFname from the EmployeeInfo table in upper case and use the ALIAS name as EmpName.

Ans:- SELECT EmpFname AS UPPER(EmpName) FROM EmployeeInfo;

Q8. Write a query find number of employees whose DOB is between 02/05/1970 to 31/12/1975 and are grouped according to gender.

Ans:- SELECT COUNT(*), Gender FROM EmployeeInfo

      WHERE DOB BETWEEN '02/05/1970 ' AND '31/12/1975' GROUP BY Gender;

Q9. Write a query to retrieve the first four characters of  EmpLname from the EmployeeInfo table.

Ans:- SELECT SUBSTRING(EmpLname, 1, 4) FROM EmployeeInfo;

Q10. Write a query to fetch all the records from the EmployeeInfo table ordered by EmpLname in descending order and Department in the ascending order.

Ans:- SELECT * FROM EmployeeInfo ORDER BY EmpLname desc, Department asc;

Q11. Write a query to fetch department-wise count of employees sorted by department’s count in ascending order.

Ans:- SELECT Department, count(EmpID) AS EmpDeptCount

      FROM EmployeeInfo GROUP BY Department

      ORDER BY EmpDeptCount ASC;

Q12. Write a SQL query to retrieve employee details from EmployeeInfo table who have a date of joining in the EmployeePosition table.

Ans:-  SELECT * FROM EmployeeInfo E

      WHERE EXISTS

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

Q13. Write a query to fetch all employees who also hold the managerial position.

Ans:- SELECT E.EmpFname, E.EmpLname, P.EmpPosition

     FROM EmployeeInfo E INNER JOIN EmployeePosition P ON

     E.EmpID = P.EmpID AndAP.EmpPosition ('Manager');

Q14. Write a query to fetch details of all employees excluding the employees with first names, “Sanjay” and “Sonia” from the EmployeeInfo table.

Ans:- SELECT * FROM EmployeeInfo WHERE EmpFname NOT IN ('Sanjay','Sonia');

Q15. Write a query to add email validation to your database.

Ans:- SELECT Email FROM EmployeeInfo

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

Q16. Write a query to retrieve Departments who have less than 2 employees working in it.

Ans:- SELECT DEPARTMENT, COUNT(EmpID) as 'EmpNo' FROM EmployeeInfo

      GROUP BY DEPARTMENT HAVING COUNT(EmpD) < 2;

Q17. Write a query to find the third-highest salary from the EmpPosition table.

Ans:-    SELECT TOP 1 salary

             FROM(

            SELECT TOP 3 salary

            FROM employee_table

            ORDER BY salary DESC) AS emp

            ORDER BY salary ASC;

Q18. Write a query to retrieve the last 3 records from the EmployeeInfo table.

Ans:-   SELECT * FROM EmployeeInfo WHERE

                    EmpID <=3 UNION SELECT * FROM

                   (SELECT * FROM EmployeeInfo E ORDER BY E.EmpID DESC)

                   AS E1 WHERE E1.EmpID <=3;

Q19. Write a query to retrieve the list of employees working in the same department.

Ans:-  Select DISTINCT E.EmpID, E.EmpFname, E.Department

                 FROM EmployeeInfo E, Employee E1

                 WHERE E.Department = E1.Department AndAE.EmpID !=   E1.EmpID;

Q20. Write a query to retrieve EmpPostion along with total salaries paid for each of them.

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

So this brings us to the end of the SQL Query  Interview Questions article. I hope this set of SQL Query Interview Questions will help you ace your job interview. All the best for your interview!

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