Top 80 + SQL Query Interview Questions and Answers with Examples

Databases, specific queries with respect to a database is provided. If the answers are same for all databases, only one query is specified. Interview Questions on SQL are based on following two tables, Employee Table and Employee Incentive Table.

Table Name : Employee

Employee_id	First_name	Last_name	Salary	Joining_date	Department
1	John	Abraham	1000000	01-JAN-13 12.00.00 AM	Banking
2	Michael	Clarke	800000	01-JAN-13 12.00.00 AM	Insurance
3	Roy	Thomas	700000	01-FEB-13 12.00.00 AM	Banking
4	Tom	Jose	600000	01-FEB-13 12.00.00 AM	Insurance
5	Jerry	Pinto	650000	01-FEB-13 12.00.00 AM	Insurance
6	Philip	Mathew	750000	01-JAN-13 12.00.00 AM	Services
7	TestName1	123	650000	01-JAN-13 12.00.00 AM	Services
8	TestName2	Lname%	600000	01-FEB-13 12.00.00 AM	Insurance

Table Name : Incentives

Employee_ref_id	Incentive_date	Incentive_amount
1	01-FEB-13	5000
2	01-FEB-13	3000
3	01-FEB-13	4000
1	01-JAN-13	4500
2	01-JAN-13	3500

SQL Queries Interview Questions and Answers on "SQL Select"

1. Get all employee details from the employee table

 Select * from employee 

2. Get First_Name,Last_Name from employee table

 Select first_name, Last_Name from employee 

3. Get First_Name from employee table using alias name “Employee Name”

 Select first_name Employee Name from employee 

4. Get First_Name from employee table in upper case

 Select upper(FIRST_NAME) from EMPLOYEE 

5. Get First_Name from employee table in lower case

Select lower(FIRST_NAME) from EMPLOYEE

6. Get unique DEPARTMENT from employee table

select distinct DEPARTMENT from EMPLOYEE

Don't Miss - SQL and Database theory Interview Questions

7. Select first 3 characters of FIRST_NAME from EMPLOYEE

Oracle Equivalent of SQL Server SUBSTRING is SUBSTR, Query : select substr(FIRST_NAME,0,3) from employee

SQL Server Equivalent of Oracle SUBSTR is SUBSTRING, Query : select substring(FIRST_NAME,1,3) from employee

MySQL Server Equivalent of Oracle SUBSTR is SUBSTRING. In MySQL start position is 1, Query : select substring(FIRST_NAME,1,3) from employee

8. Get position of 'o' in name 'John' from employee table

Oracle Equivalent of SQL Server CHARINDEX is INSTR, Query : Select instr(FIRST_NAME,'o') from employee where first_name='John'

SQL Server Equivalent of Oracle INSTR is CHARINDEX, Query: Select CHARINDEX('o',FIRST_NAME,0) from employee where first_name='John'

MySQL Server Equivalent of Oracle INSTR is LOCATE, Query: Select LOCATE('o',FIRST_NAME) from employee where first_name='John'

9. Get FIRST_NAME from employee table after removing white spaces from right side

select RTRIM(FIRST_NAME) from employee

10. Get FIRST_NAME from employee table after removing white spaces from left side

select LTRIM(FIRST_NAME) from employee

11. Get length of FIRST_NAME from employee table

Oracle,MYSQL Equivalent of SQL Server Len is Length , Query :select length(FIRST_NAME) from employee

SQL Server Equivalent of Oracle,MYSQL Length is Len, Query :select len(FIRST_NAME) from employee

12. Get First_Name from employee table after replacing 'o' with '$'

select REPLACE(FIRST_NAME,'o','$') from employee

13. Get First_Name and Last_Name as single column from employee table separated by a '_'

Oracle Equivalent of MySQL concat is '||', Query : Select FIRST_NAME|| '_' ||LAST_NAME from EMPLOYEE

SQL Server Equivalent of MySQL concat is '+', Query : Select FIRST_NAME + '_' +LAST_NAME from EMPLOYEE

MySQL Equivalent of Oracle '||' is concat, Query : Select concat(FIRST_NAME,'_',LAST_NAME) from EMPLOYEE

14. Get FIRST_NAME ,Joining year,Joining Month and Joining Date from employee table

SQL Queries in Oracle, Select FIRST_NAME, to_char(joining_date,'YYYY') JoinYear , to_char(joining_date,'Mon'), to_char(joining_date,'dd') from EMPLOYEE

SQL Queries in SQL Server, select SUBSTRING (convert(varchar,joining_date,103),7,4) , SUBSTRING (convert(varchar,joining_date,100),1,3) , SUBSTRING (convert(varchar,joining_date,100),5,2) from EMPLOYEE

SQL Queries in MySQL, select year(joining_date),month(joining_date), DAY(joining_date) from EMPLOYEE

15. Get all employee details from the employee table order by First_Name Ascending

Select * from employee order by FIRST_NAME asc
16. Get all employee details from the employee table order by First_Name descending
Select * from employee order by FIRST_NAME desc

17. Get all employee details from the employee table order by First_Name Ascending and Salary descending
Select * from employee order by FIRST_NAME asc,SALARY desc

"SQL Where Condition" Interview Questions
18. Get employee details from employee table whose employee name is “John”
Select * from EMPLOYEE where FIRST_NAME='John'
19. Get employee details from employee table whose employee name are “John” and “Roy”
Select * from EMPLOYEE where FIRST_NAME in ('John','Roy')
20. Get employee details from employee table whose employee name are not “John” and “Roy”
Select * from EMPLOYEE where FIRST_NAME not in ('John','Roy')

"SQL Wild Card Search" Interview Questions
21. Get employee details from employee table whose first name starts with 'J'
Select * from EMPLOYEE where FIRST_NAME like 'J%'
22. Get employee details from employee table whose first name contains 'o'
Select * from EMPLOYEE where FIRST_NAME like '%o%'
23. Get employee details from employee table whose first name ends with 'n'
Select * from EMPLOYEE where FIRST_NAME like '%n'
"SQL Pattern Matching" Interview Questions
24. Get employee details from employee table whose first name ends with 'n' and name contains 4 letters
Select * from EMPLOYEE where FIRST_NAME like '___n' (Underscores)
25. Get employee details from employee table whose first name starts with 'J' and name contains 4 letters
Select * from EMPLOYEE where FIRST_NAME like 'J___' (Underscores)
26. Get employee details from employee table whose Salary greater than 600000
Select * from EMPLOYEE where Salary >600000
27. Get employee details from employee table whose Salary less than 800000
Select * from EMPLOYEE where Salary <800000
28. Get employee details from employee table whose Salary between 500000 and 800000
Select * from EMPLOYEE where Salary between 500000 and 800000
29. Get employee details from employee table whose name is 'John' and 'Michael'
Select * from EMPLOYEE where FIRST_NAME in ('John','Michael')