SQL BASIC INTERVIEW QUESTIONS AND ANSWERS: PART 1

SQL BASIC INTERVIEW QUESTIONS AND ANSWERS : PART 1

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

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,0,3) 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

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

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')

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'

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')

39. Get names of employees from employee table who has '%' in Last_Name. Tip : Escape character for special characters in a query.

SQL Queries in Oracle, Select FIRST_NAME from employee where Last_Name like '%?%%'

SQL Queries in SQL Server, Select FIRST_NAME from employee where Last_Name like '%[%]%'

40. Get Last Name from employee table after replacing special character with white space

SQL Queries in Oracle, Select translate(LAST_NAME,'%',' ') from employee

SQL Queries in SQL Server and MySQL, Select REPLACE(LAST_NAME,'%',' ') from employee

41. Get department,total salary with respect to a department from employee table.

Select DEPARTMENT,sum(SALARY) Total_Salary from employee group by department

42. Get department,total salary with respect to a department from employee table order by total salary descending

Select DEPARTMENT,sum(SALARY) Total_Salary from employee group by DEPARTMENT order by Total_Salary descending

43. Get department,no of employees in a department,total salary with respect to a department from employee table order by total salary descending

Select DEPARTMENT,count(FIRST_NAME),sum(SALARY) Total_Salary from employee group by DEPARTMENT order by Total_Salary descending

44. Get department wise average salary from employee table order by salary ascending

select DEPARTMENT,avg(SALARY) AvgSalary from employee group by DEPARTMENT order by AvgSalary asc

45. Get department wise maximum salary from employee table order by salary ascending

select DEPARTMENT,max(SALARY) MaxSalary from employee group by DEPARTMENT order by MaxSalary asc

46. Get department wise minimum salary from employee table order by salary ascending

select DEPARTMENT,min(SALARY) MinSalary from employee group by DEPARTMENT order by MinSalary asc

58. Select Nth Highest salary from employee table

SQL Queries in Oracle, select min(salary) from (select * from (select * from employee order by SALARY desc) where rownum < N + 1)

SQL Queries in SQL Server, select min(SALARY) from (select top N * from employee) a