!["SQL Escape Characters" Interview Questions
39. Get names of employees from employee table who has '%' in Last_Name. Tip :
Escape character for special characters in a query.
A)Select First_Name from employee where Last_Name like '%[%]%'
40. Get Last Name from employee table after replacing special character with
white space
A) Select REPLACE(LAST_NAME,'%',' ') from employee
"SQL Group By Query" Interview Questions and Answers
41. Get department,total salary with respect to a department from employee table.
A) 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
A) Select Department,sum(Salary) Total_Salary from employee group by Department
order by Total_Salary descending
A
SQL Queries Interview Questions and Answers on "SQL
Mathematical Operations using Group By"
43. Get department,no of employees in a department,total salary with respect to a
department from employee table order by total salary descending
A) 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](https://image.slidesharecdn.com/raviquerys425-170406102421/85/Ravi-querys-425-7-320.jpg)
Ravi querys 425
- 1. TABLE NAME:Empolyee Create table Employee(Employee_id int, First_Name varchar(50),Last_Name varchar(50),Salary momey,Department varchar(50)) INSERT INTO Employee values( 1,’John’,’Abraham’,1000000,’01-JAN-13 12.00.00 AM’,’BANKING’) INSERT INTO Employee values(2,’Michael’,’Clark’,800000,’01-JAN-13 12.00.00 AM’,’INSURANCE’) INSERT INTO Employee values(3,Roy’,’Thomas’,700000,’01-FEB-13 12.00.00 AM’,BANKING’) INSERT INTO Employee values(4,’Tom’,’Jose’,600000,’01-FEB-13 12.00.00 AM’,’INSURANCE’) INSERT INTO Employee values(5,’Jerry’,’Pinto’,650000,’01-FEB-13 12.00.00 AM’,’INSURANCE’) INSERT INTO Employee values(6,’Philip’,’Mathew’,750000,’01-JAN-13 12.00.00 AM’,SERVICES’) INSERT INTO Employee values(7,’TestName1’,’123’,650000,’01-JAN-13 12.00.00 AM’,’SERVICES’) I INSERT INTO Employee values(8,’TestName’,’Lname%’,600000,’01- FEB-13 12.00.00AM’,’INSURANCE’,) TABLE NAME:Incentives Create table Incentives(Employee_ref_id int,Incentives_date varchar(50),Incentives_amount money) INSERT INTO Incentives values(1,’01-FEB-13’,5000) INSERT INTO Incentives values(2,’01-FEB-13’,3000) INSERT INTO Incentives values(3,’01-FEB-13’,4000) INSERT INTO Incentives values(1,’01-JAN-13’,4500) INSERT INTO Incentives values(2,’01-JAN-13’,3500)
- 2. SQL Queries Interview Questions and Answers on "SQL Selec0t" 1. Get all employee details from the employee table A) select*from Employee or B) select Employee_id,First_Name,Last_name,Salary,Department 2. Get First_Name,Last_Name from employee table A) Select first_name, Last_Name from employee 3. Get First_Name from employee table using alias name “Employee Name” A) Select first_name Employee_ Name from employee 4. Get First_Name from employee table in upper case A) Select upper(First_Name) from EMPLOYEE 5. Get First_Name from employee table in lower case A) Select lower(First_Name) from EMPLOYEE 6. Get unique DEPARTMENT from employee table A) select distinct Department from EMPLOYEE 7. Select first 3 characters of FIRST_NAME from EMPLOYEE A) select substr(First_Name,1,3) from employee OR A) select substring(First_Name,1,3) from employee
- 3. 8. Get position of 'o' in name 'John' from employee table A) Select CHARINDEX('o',First_Name,0) from employee where first_name='John' 9. Get FIRST_NAME from employee table after removing white spaces from right side A) select RTRIM(First_Name) from employee 10. Get FIRST_NAME from employee table after removing white spaces from left side A) select LTRIM(First_Name) from employee 11. Get length of FIRST_NAME from employee table A) select len(First_Name) from employee 12. Get First_Name from employee table after replacing 'o' with '$' A) select REPLACE(First_Name,'o','$') from employee 13. Get First_Name and Last_Name as single column from employee table separated by a '_' A) Select First_Name + '_' +Last_Name from EMPLOYEE 14. Get FIRST_NAME ,Joining year,Joining Month and Joining Date from employee table A)
- 4. "SQL Order By" Interview Questions 15. Get all employee details from the employee table order by First_Name Ascending A) Select * from employee order by First_Name asc 16. Get all employee details from the employee table order by First_Name descending A) 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 A) 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” A) Select * from EMPLOYEE where First_Name='John' 19. Get employee details from employee table whose employee name are “John” and “Roy” A) Select * from EMPLOYEE where First_Name in ('John','Roy') 20. Get employee details from employee table whose employee name are not “John” and “Roy” A) Select * from EMPLOYEE where First_Name not in ('John','Roy')
- 5. "SQL Wild Card Search" Interview Questions 21. Get employee details from employee table whose first name starts with 'J' A) Select * from EMPLOYEE where First_Name like 'J%' 22. Get employee details from employee table whose first name contains 'o' A) Select * from EMPLOYEE where First_Name like '%o% 23. Get employee details from employee table whose first name ends with 'n' A) 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 A) Select * from EMPLOYEE where First_Name like '___n' 25. Get employee details from employee table whose first name starts with 'J' and name contains 4 letters A) Select * from EMPLOYEE where First_Name like 'J___' 26. Get employee details from employee table whose Salary greater than 600000 A) Select * from EMPLOYEE where Salary >600000 27. Get employee details from employee table whose Salary less than 800000 A) Select * from EMPLOYEE where Salary <800000 28. Get employee details from employee table whose Salary between 500000 and 800000
- 6. A) Select * from EMPLOYEE where Salary between 500000 and 800000 29. Get employee details from employee table whose name is 'John' and 'Michael' A) Select * from EMPLOYEE where First_Name in ('John','Michael') Interview Questions on "SQL DATE Functions" 30. Get employee details from employee table whose joining year is “2013” A) 31. Get employee details from employee table whose joining month is “January” A) 32. Get employee details from employee table who joined before January 1st 2013 A) Select * from EMPLOYEE where joining_date <'01/01/2013' 33. Get employee details from employee table who joined after January 31st A) Select * from EMPLOYEE where joining_date >'01/31/2013' 35. Get Joining Date and Time from employee table A) select convert(varchar(50),joining_date) from EMPLOYEE 36. Get Joining Date,Time including milliseconds from employee table A) select convert(varchar,joining_date) from EMPLOYEE 37. Get difference between JOINING_DATE and INCENTIVE_DATE from employee and incentives table A) 38. Get database date A) select getdate()
- 7. "SQL Escape Characters" Interview Questions 39. Get names of employees from employee table who has '%' in Last_Name. Tip : Escape character for special characters in a query. A)Select First_Name from employee where Last_Name like '%[%]%' 40. Get Last Name from employee table after replacing special character with white space A) Select REPLACE(LAST_NAME,'%',' ') from employee "SQL Group By Query" Interview Questions and Answers 41. Get department,total salary with respect to a department from employee table. A) 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 A) Select Department,sum(Salary) Total_Salary from employee group by Department order by Total_Salary descending A SQL Queries Interview Questions and Answers on "SQL Mathematical Operations using Group By" 43. Get department,no of employees in a department,total salary with respect to a department from employee table order by total salary descending A) 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
- 8. A) 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 A) select Department,max(SALARY) MaxSalary from employee group by Departmet order by MaxSalary asc 46. Get department wise minimum salary from employee table order by salary ascending A) select Department ,min(salary) MinSalary from employee group by Department order by MinSalary asc 47. Select no of employees joined with respect to year and month from employee table 48. Select department,total salary with respect to a department from employee table where total salary greater than 800000 order by Total_Salary descending A) Select Department,sum(Salary) Total_Salary from employee group by Department having sum(Salary) >800000 order by Total_Salary desc Advanced SQL Queries Interview Questions and Answers 49. Select employee details from employee table if data exists in incentive table ? A) select * from EMPLOYEE where exists (select * from INCENTIVES) Explanation : Here "exists" statement helps us to do the job of If statement. Main query will get executed if the sub query returns at least one row. So we can consider the sub query as "If condition" and the main query as "code block" inside the If condition. We can use any SQL commands (Joins, Group By , having etc) in sub query. This command will be useful in queries which need to detect an event and do some activity.
- 9. 50. How to fetch data that are common in two query results ? A) Explanation : Here "INTERSECT" command is used to fetch data that are common in 2 queries. In this example, we had taken EMPLOYEE table in both the queries.We can apply INTERSECT command on different tables. The result of the above query will return employee details of "ROY" because, employee id of ROY is 3, and both query results have the information about ROY. 51. Get Employee ID's of those employees who didn't receive incentives without using sub query ? A) select EMPLOYEE_ID from EMPLOYEE MINUS select Employee_ref_id from Incentives Explanation : To filter out certain information we use MINUS command. What MINUS Command odes is that, it returns all the results from the first query, that are not part of the second query. In our example, first three employees received the incentives. So query will return employee id's 4 to 8. 52. Select 20 % of salary from John , 10% of Salary for Roy and for other 15 % of salary from employee table A) select First_Name, case First_Name when'John' then salary * .2 when 'Roy' then salary * .10 else salary * .15 end "Deduced_Amount" from EMPLOYEE Explanation : Here, we are using "SQL CASE" statement to achieve the desired results. After case statement, we had to specify the column on which filtering is applied. In our case it is "FIRST_NAME". And in then condition, specify the name of filter like John, Roy etc. To handle conditions outside our filter, use else block where every one other than John and Roy enters. 53. Select Banking as 'Bank Dept', Insurance as 'Insurance Dept' and Services as 'Services Dept' from employee table A)
- 10. Explanation : Here "DECODE" keyword is used to specify the alias name. In oracle we had specify, Column Name followed by Actual Name and Alias Name as arguments. In SQL Server and MySQL, we can use the earlier switch case statements for alias names. 54. Delete employee data from employee table who got incentives in incentive table A) delete from EMPLOYEE where EMPLOYEE_ID in (select EMPLOYEE_REF_ID from INCENTIVES) Explanation : Trick about this question is that we can't delete data from a table based on some condition in another table by joining them. Here to delete multiple entries from EMPLOYEE table, we need to use Subquery. Entries will get deleted based on the result of Subquery. 55. Insert into employee table Last Name with " ' " (Single Quote - Special Character) A) Insert into employee (LAST_NAME) values ('Test''') 56. Select Last Name from employee table which contain only numbers A) Select * from EMPLOYEE where lower(Last_Name)=upper(Last_Name) Explanation : In order to achieve the desired result, we use "ASCII" property of the database. If we get results for a column using Lower and Upper commands, ASCII of both results will be same for numbers. If there is any alphabets in the column, results will differ. 57. Write a query to rank employees based on their incentives for a month A) Explanation : In order to rank employees based on their rank for a month, "DENSE_RANK" keyword is used. Here partition by keyword helps us to sort the column with which filtering is done. Rank is provided to the column specified in the order by statement. The above query ranks employees with respect to their incentives for a
- 11. given month. 58. Update incentive table where employee name is 'John' A) update INCENTIVES set INCENTIVE_AMOUNT='9000' where EMPLOYEE_REF_ID=(select EMPLOYEE_ID from EMPLOYEE where FIRST_NAME='John' ) Explanation : We need to join Employee and Incentive Table for updating the incentive amount. But for update statement joining query wont work. We need to use sub query to update the data in the incentive table. SQL Query is as shown below. "SQL Join" Interview Questions 59. Select first_name, incentive amount from employee and incentives table for those employees who have incentives A) Select First_Name,INCENTIVES_AMOUNT from employee a inner join incentives B on A.EMPLOYEE_ID=B.EMPLOYEE_REF_ID 60. Select first_name, incentive amount from employee and incentives table for those employees who have incentives and incentive amount greater than 3000 A) Select First_Name,INCENTIVES_AMOUNT from employee a inner join incentives B on A.EMPLOYEE_ID=B.EMPLOYEE_REF_ID and INCENTIVE_AMOUNT >3000 61. Select first_name, incentive amount from employee and incentives table for all employes even if they didn't get incentives A) Select First_Name,INCENTIVES_AMOUNT from employee a left join incentives B on A.EMPLOYEE_ID=B.EMPLOYEE_REF_ID
- 12. 62. Select first_name, incentive amount from employee and incentives table for all employees even if they didn't get incentives and set incentive amount as 0 for those employees who didn't get incentives. A) Select FIRST_NAME, ISNULL(INCENTIVE_AMOUNT,0) from employee a left join incentives B on A.EMPLOYEE_ID=B.EMPLOYEE_REF_ID 63. Select first_name, incentive amount from employee and incentives table for all employees who got incentives using left join A ) Select First_Name, is null(INCENTIVES_AMOUNT,0) from employee a right join incentives B on A.EMPLOYEE_ID=B.EMPLOYEE_REF_ID 64. Select max incentive with respect to employee from employee and incentives table using sub query A) select Department,(select is null9max(incentives_amount),0) from incentives where EMPLOYEE_ref_ if=EMPLOYEE_id) max_incentives from EMPLOYEE "Top N Salary" SQL Interview Questions and Answers 65. Select TOP 2 salary from employee table A) select top(2)*from EMPLOYEE 66. Select TOP N salary from employee table A) select top(N)*from EMPLOYEE 67. Select 2nd Highest salary from employee table A) select min(Salary) from (select top 2 * from EMPLOYEE) a 68. Select Nth Highest salary from employee table A) select min(salary) from (select top n *from EMPLOYEE "SQL Union" Query Interview Questions 69. Select First_Name,LAST_NAME from employee table as separate rows
- 13. A) select First_Name from EMPLOYEE union select Last_Name from EMPLOYEE 70. What is the difference between UNION and UNION ALL ? SQL Interview Questions on "SQL Table Scripts" 71. Write create table syntax for employee table A) CREATE TABLE EMPLOYEE( EMPLOYEE_ID int, First_Name varchar(50) , Last_Name varchar(50) , SALARY money, jonining_date varchar(50), Department varchar(50) ) 72. Write syntax to delete table employee A) Drop table EMPLOYEE or A) delete from EMPLOYEE 73. Write syntax to set EMPLOYEE_ID as primary key in employee table 74. Write syntax to set 2 fields(EMPLOYEE_ID,FIRST_NAME) as primary key in employee table 75. Write syntax to drop primary key on employee table A) Alter TABLE EMPLOYEE drop CONSTRAINT EMPLOYEE_PK
- 14. 76. Write Sql Syntax to create EMPLOYEE_REF_ID in INCENTIVES table as foreign key with respect to EMPLOYEE_ID in employee table 77. Write SQL to drop foreign key on employee table A) ALTER TABLE INCENTIVES drop CONSTRAINT INCENTIVES_FK 78. Write SQL to create Orcale Sequence 79. Write Sql syntax to create Oracle Trigger before insert of each row in employee table 80. Oracle Procedure81. Oracle View 82. Oracle materialized view - Daily Auto Refresh 83. Oracle materialized view - Fast Refresh on Commit 84. What is SQL Injection ? A) SQL Injection is one of the the techniques uses by hackers to hack a website by injecting SQL commands in data fields.