TOP 50 SQl queries for interview

— Q-1. Write an SQL query to fetch “FIRST_NAME” from

Worker table using the alias name as <WORKER_NAME>. select first_name AS WORKER_NAME from worker;

— Q-2. Write an SQL query to fetch “FIRST_NAME” from
Worker table in upper case.

select UPPER(first_name) from worker;

— Q-3. Write an SQL query to fetch unique values of DEPARTMENT from Worker table.
SELECT distinct department from worker;

— Q-4. Write an SQL query to print the first three characters of FIRST_NAME from Worker table. select substring(first_name, 1, 3) from worker;

— Q-5. Write an SQL query to find the position of the alphabet („b‟) in the first name column „Amitabh‟ from

Worker table.

select INSTR(first_name, ‘B’) from worker where first_name = ‘Amitabh’;

— Q-6. Write an SQL query to print the FIRST_NAME from Worker table after removing white spaces from the right side.

select RTRIM(first_name) from worker;

— Q-7. Write an SQL query to print the DEPARTMENT from Worker table after removing white spaces from the left side.

select LTRIM(first_name) from worker;

— Q-8. Write an SQL query that fetches the unique

values of DEPARTMENT from Worker table and prints its length.

select distinct department, LENGTH(department) from worker;

— Q-9. Write an SQL query to print the FIRST_NAME from
Worker table after replacing „a‟ with „A‟.
select REPLACE(first_name, ‘a’, ‘A’) from worker;

— Q-10. Write an SQL query to print the FIRST_NAME and LAST_NAME from Worker table into a single column
COMPLETE_NAME.
— A space char should separate them.

select CONCAT(first_name, ‘ ‘, last_name) AS COMPLETE_NAME from worker;

— Q-11. Write an SQL query to print all Worker details from the Worker table order by FIRST_NAME Ascending. select * from worker ORDER by first_name;

— Q-12. Write an SQL query to print all Worker details from the Worker table order by

— FIRST_NAME Ascending and DEPARTMENT Descending. select * from worker order by first_name, department DESC;

— Q-13. Write an SQL query to print details for

Workers with the first name as “Vipul” and “Satish” from Worker table.

select * from worker where first_name IN (‘Vipul’, ‘Satish’);

— Q-14. Write an SQL query to print details of workers excluding first names, “Vipul” and “Satish” from Worker table.

select * from worker where first_name NOT IN (‘Vipul’, ‘Satish’);

— Q-15. Write an SQL query to print details of Workers with DEPARTMENT name as “Admin*”.

select * from worker where department LIKE ‘Admin%’;

— Q-16. Write an SQL query to print details of the Workers whose FIRST_NAME contains „a‟.
select * from worker where first_name LIKE ‘%a%’;


— Q-17. Write an SQL query to print details of the
Workers whose FIRST_NAME ends with „a‟.
select * from worker where first_name LIKE ‘%a’;

— Q-18. Write an SQL query to print details of the

Workers whose FIRST_NAME ends with „h‟ and contains six alphabets.
select * from worker where first_name LIKE ‘_____h’;

— Q-19. Write an SQL query to print details of the Workers whose SALARY lies between 100000 and 500000. select * from worker where salary between 100000 AND 500000;

— Q-20. Write an SQL query to print details of the

Workers who have joined in Feb‟2014.

select * from worker where YEAR(joining_date) = 2014 AND MONTH(joining_date) = 02;

— Q-21. Write an SQL query to fetch the count of employees working in the department „Admin‟. select department, count(*) from worker where department = ‘Admin’;

— Q-22. Write an SQL query to fetch worker full names with salaries >= 50000 and <= 100000.

select concat(first_name, ‘ ‘, last_name) from worker where salary between 50000 and 100000;

— Q-23. Write an SQL query to fetch the no. of workers for each department in the descending order.

select department, count(worker_id) AS no_of_worker from worker group by department
ORDER BY no_of_worker desc;

— Q-24. Write an SQL query to print details of the Workers who are also Managers.


select w.* from worker as w inner join title as t on w.worker_id = t.worker_ref_id where t.worker_title = ‘Manager’;

— Q-25. Write an SQL query to fetch number (more than

1) of same titles in the ORG of different types. select worker_title, count(*) as count from title group by worker_title having count > 1;

— Q-26. Write an SQL query to show only odd rows from a table.

— select * from worker where MOD (WORKER_ID, 2) != 0; select * from worker where MOD (WORKER_ID, 2) <> 0;

— Q-27. Write an SQL query to show only even rows from a table.

select * from worker where MOD (WORKER_ID, 2) = 0;

— Q-28. Write an SQL query to clone a new table from another table.
CREATE TABLE worker_clone LIKE worker;

INSERT INTO worker_clone select * from worker; select * from worker_clone;

— Q-29. Write an SQL query to fetch intersecting records of two tables.

select worker.* from worker inner join worker_clone using(worker_id);

— Q-30. Write an SQL query to show records from one table that another table does not have.
— MINUS

select worker.* from worker left join worker_clone using(worker_id) WHERE worker_clone.worker_id is NULL;

— Q-31. Write an SQL query to show the current date and time.
— DUAL
select curdate();
select now();


— Q-32. Write an SQL query to show the top n (say 5) records of a table order by descending salary. select * from worker order by salary desc LIMIT 5;

— Q-33. Write an SQL query to determine the nth (say n=5) highest salary from a table.
select * from worker order by salary desc LIMIT 4,1;

— Q-34. Write an SQL query to determine the 5th highest salary without using LIMIT keyword. select salary from worker w1

WHERE 4 = (

SELECT COUNT(DISTINCT (w2.salary)) from worker w2

where w2.salary >= w1.salary );

— Q-35. Write an SQL query to fetch the list of employees with the same salary.

select w1.* from worker w1, worker w2 where w1.salary = w2.salary and w1.worker_id != w2.worker_id;

— Q-36. Write an SQL query to show the second highest salary from a table using sub-query.
select max(salary) from worker
where salary not in (select max(salary) from worker);

— Q-37. Write an SQL query to show one row twice in results from a table.
select * from worker
UNION ALL
select * from worker ORDER BY worker_id;

— Q-38. Write an SQL query to list worker_id who does not get bonus.

select worker_id from worker where worker_id not in (select worker_ref_id from bonus);


— Q-39. Write an SQL query to fetch the first 50% records from a table.

select * from worker where worker_id <= ( select count(worker_id)/2 from worker);

— Q-40. Write an SQL query to fetch the departments that have less than 4 people in it.

select department, count(department) as depCount from worker group by department having depCount < 4;

— Q-41. Write an SQL query to show all departments along with the number of people in there.

select department, count(department) as depCount from worker group by department;

— Q-42. Write an SQL query to show the last record from a table.

select * from worker where worker_id = (select max(worker_id) from worker);

— Q-43. Write an SQL query to fetch the first row of a table.

select * from worker where worker_id = (select min(worker_id) from worker);

— Q-44. Write an SQL query to fetch the last five records from a table.

(select * from worker order by worker_id desc limit 5) order by worker_id;

— Q-45. Write an SQL query to print the name of employees having the highest salary in each department. select w.department, w.first_name, w.salary from (select max(salary) as maxsal, department from worker group by department) temp

inner join worker w on temp.department = w.department and temp.maxsal = w.salary;

— Q-46. Write an SQL query to fetch three max salaries from a table using co-related subquery

select distinct salary from worker w1

where 3 >= (select count(distinct salary) from worker w2 where w1.salary <= w2.salary) order by w1.salary desc;

— DRY RUN AFTER REVISING THE CORELATED SUBQUERY CONCEPT FROM LEC-9.

select distinct salary from worker order by salary desc limit 3;

— Q-47. Write an SQL query to fetch three min salaries from a table using co-related subquery

select distinct salary from worker w1

where 3 >= (select count(distinct salary) from worker w2 where w1.salary >= w2.salary) order by w1.salary desc;

— Q-48. Write an SQL query to fetch nth max salaries from a table.
select distinct salary from worker w1

where n >= (select count(distinct salary) from worker w2 where w1.salary <= w2.salary) order by w1.salary desc;

— Q-49. Write an SQL query to fetch departments along with the total salaries paid for each of them. select department , sum(salary) as depSal from worker group by department order by depSal desc;

— Q-50. Write an SQL query to fetch the names of workers who earn the highest salary.

select first_name, salary from worker where salary = (select max(Salary) from worker);