Monday, June 30, 2014

SQL Query Practice - Interview Question and Answers

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

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

        SELECT FIRST_NAME AS NAME FROM EMPLOYEE
4.      Get First_Name from employee table in upper case
SELECT UPPER(FIRST_NAME) AS FIRST_NAME FROM EMPLOYEE
5.      Get First_Name from employee table in lower case
SELECT LOWER(FIRST_NAME) AS 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
SELECT SUBSTRING(FIRST_NAME,1,3) AS FIRST_NAME FROM EMPLOYEE
8.      Get position of 'o' in name 'John' from employee table
SELECT  CHARINDEX('O',FIRST_NAME) AS POSITION FROM EMPLOYEE WHERE FIRST_NAME='JOHN'
9.      Get FIRST_NAME from employee table after removing white spaces from right side
SELECT RTRIM(FIRST_NAME) AS FIRST_NAME FROM EMPLOYEE
10.  Get FIRST_NAME from employee table after removing white spaces from left side
SELECT LTRIM(FIRST_NAME) AS FIRST_NAME FROM EMPLOYEE
11.  Get length of FIRST_NAME from employee table
SELECT LEN(FIRST_NAME) AS LENGTH FROM EMPLOYEE
12.  Get First_Name from employee table after replacing 'o' with '$'
SELECT REPLACE(FIRST_NAME,'O','$') AS FIRST_NAME FROM EMPLOYEE
13.  Get First_Name and Last_Name as single column from employee table separated by a '_'
SELECT FIRST_NAME +'_'+ LAST_NAME AS NAME  FROM EMPLOYEE
14.  Get FIRST_NAME ,Joining year,Joining Month and Joining Date from employee table
SELECT FIRST_NAME,YEAR(JOINING_DATE) AS YEAR,MONTH(JOINING_DATE) AS MONTH,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
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
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' AND LEN(FIRST_NAME)=4
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%' AND LEN(FIRST_NAME)=4
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')
30.  Get employee details from employee table whose joining year is “2013”
SELECT * FROM EMPLOYEE WHERE YEAR(JOINING_DATE)=2013
31.  Get employee details from employee table whose joining month is “January”
SELECT * FROM EMPLOYEE WHERE   DATENAME(MONTH,JOINING_DATE) ='January'
32.  Get employee details from employee table who joined before January 1st 2013
SELECT * FROM EMPLOYEE WHERE   JOINING_DATE < '1-1-2013'
33.  Get employee details from employee table who joined after January 31st
SELECT * FROM EMPLOYEE WHERE   JOINING_DATE > '1-31-2013'
34.  Get Joining Date and Time from employee table
SELECT JOINING_DATE FROM EMPLOYEE
35.  Get Joining Date,Time including milliseconds from employee table
SELECT CONVERT(DATE,JOINING_DATE,103) AS DATE,CONVERT(time,JOINING_DATE,101) as TIME FROM EMPLOYEE
36.  Get difference between JOINING_DATE and INCENTIVE_DATE from employee and incentives table
SELECT DATEDIFF(DAY,EMP.JOINING_DATE,INS.INCENTIVE_DATE) AS DATE_DIFF FROM EMPLOYEE EMP INNER JOIN INCENTIVE INS ON INS.EMPLOYEE_RFF_ID=EMP.EMPLOYEE_ID
37.  Get database date
SELECT  GETDATE() AS DATE
38.  Get names of employees from employee table who has '%' in Last_Name. Tip : Escape character for special characters in a query.
SELECT FIRST_NAME +' '+LAST_NAME FROM EMPLOYEE WHERE LAST_NAME LIKE '%\%%' ESCAPE '\'
39.  Get Last Name from employee table after replacing special character with white space
SELECT REPLACE(REPLACE(REPLACE(REPLACE(LAST_NAME,'%',''),'1',''),'2',''),'3','') FROM  EMPLOYEE
40.  Get department,total salary with respect to a department from employee table.
SELECT DEPARTMENT,SUM(SALARY) AS SALARY FROM EMPLOYEE GROUP BY DEPARTMENT
41.  Get department,total salary with respect to a department from employee table order by total salary descending
SELECT DEPARTMENT,SUM(SALARY) AS SALARY FROM EMPLOYEE  GROUP BY DEPARTMENT ORDER BY SALARY DESC
42.  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,SUM(SALARY) AS SALARY,COUNT(EMPLOYEE_ID) AS EMP_COUNT FROM EMPLOYEE  GROUP BY DEPARTMENT ORDER BY SALARY DESC 
43.  Get department wise average salary from employee table order by salary ascending
SELECT (X.SALARY/X.EMP_COUNT) AVERAGE_SALARY FROM (SELECT SUM(SALARY) AS SALARY ,COUNT(EMPLOYEE_ID) AS EMP_COUNT FROM EMPLOYEE GROUP BY DEPARTMENT ) AS X  ORDER BY X.SALARY
44.  Get department wise maximum salary from employee table order by salary ascending
SELECT MAX(SALARY) AS MAX_SALARY FROM EMPLOYEE GROUP BY DEPARTMENT ORDER BY MAX_SALARY
45.  Get department wise minimum salary from employee table order by salary ascending
SELECT MIN(SALARY) AS MIN_SALARY FROM EMPLOYEE GROUP BY DEPARTMENT ORDER BY MIN_SALARY
46.  Select no of employees joined with respect to year and month from employee table
SELECT COUNT(EMPLOYEE_ID) AS EMP_COUNT,YEAR(JOINING_DATE)AS YEAR, MONTH(JOINING_DATE)AS MONTH FROM EMPLOYEE GROUP BY YEAR(JOINING_DATE),MONTH(JOINING_DATE)

 
47.  Select department,total salary with respect to a department from employee table where total salary greater than 800000 order by Total_Salary descending
SELECT X.* FROM(SELECT DEPARTMENT,SUM(SALARY) AS TOTAL FROM EMPLOYEE GROUP BY DEPARTMENT ) AS X WHERE X.TOTAL>800000 ORDER BY X.TOTAL DESC
48.  Select first_name, incentive amount from employee and incentives table for those employees who have incentives
SELECT EMP.FIRST_NAME,INS.INCENTIVE_AMOUNT FROM EMPLOYEE EMP INNER JOIN INCENTIVE INS ON INS.EMPLOYEE_RFF_ID=EMP.EMPLOYEE_ID
49.  Select first_name, incentive amount from employee and incentives table for those employees who have incentives and incentive amount greater than 3000
SELECT EMP.FIRST_NAME,INS.INCENTIVE_AMOUNT FROM EMPLOYEE EMP INNER JOIN INCENTIVE INS ON INS.EMPLOYEE_RFF_ID=EMP.EMPLOYEE_ID WHERE INS.INCENTIVE_AMOUNT>3000
50.  Select first_name, incentive amount from employee and incentives table for all employes even if they didn't get incentives
SELECT EMP.FIRST_NAME,INS.INCENTIVE_AMOUNT FROM EMPLOYEE EMP LEFT JOIN INCENTIVE INS ON INS.EMPLOYEE_RFF_ID=EMP.EMPLOYEE_ID
51.   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.
SELECT EMP.FIRST_NAME,ISNULL(INS.INCENTIVE_AMOUNT,0)AS INCENTIVE_AMOUNT FROM EMPLOYEE EMP LEFT JOIN INCENTIVE INS ON INS.EMPLOYEE_RFF_ID=EMP.EMPLOYEE_ID
52.   Select first_name, incentive amount from employee and incentives table for all employees who got incentives using left join
SELECT EMP.FIRST_NAME,INS.INCENTIVE_AMOUNT FROM INCENTIVE INS LEFT JOIN EMPLOYEE EMP ON EMP.EMPLOYEE_ID=INS.EMPLOYEE_RFF_ID
53.   Select max incentive with respect to employee from employee and incentives table using sub query

SELECT X.FIRST_NAME,MAX(X.INCENTIVE_AMOUNT) AS MAX_AMOUND FROM
(SELECT EMP.FIRST_NAME,INS.INCENTIVE_AMOUNT FROM INCENTIVE INS INNER JOIN EMPLOYEE EMP ON EMP.EMPLOYEE_ID=INS.EMPLOYEE_RFF_ID) AS X GROUP BY X.FIRST_NAME
54.   Select TOP 2 salary from employee table
SELECT TOP 2 SALARY FROM EMPLOYEE ORDER BY SALARY DESC
55.   Select TOP N salary from employee table
DECLARE @N INT = 4
SELECT TOP(@N) SALARY FROM EMPLOYEE ORDER BY SALARY DESC
56.   Select 2nd Highest salary from employee table
SELECT MIN(X.SALARY) AS MIN_SALARY FROM(SELECT TOP 2 SALARY FROM EMPLOYEE) AS X
57.   Select Nth Highest salary from employee table
SELECT X.SALARY FROM
(SELECT EMP.SALARY,RANK() OVER(ORDER BY SALARY DESC) AS ROW FROM EMPLOYEE EMP) AS X WHERE X.ROW=2
58.   Select First_Name,LAST_NAME from employee table as separate rows
SELECT FIRST_NAME FROM EMPLOYEE UNION
SELECT LAST_NAME FROM EMPLOYEE
59.          What is the difference between UNION and UNION ALL ?
UNION
The UNION command is used to select related information from two tables, much like the JOIN command. However, when using the UNION command all selected columns need to be of the same data type. With UNION, only distinct values are selected.
UNION ALL
The UNION ALL command is equal to the UNION command, except that UNION ALL selects all values.
The difference between Union and Union all is that Union all will not eliminate duplicate rows, instead it just pulls all rows from all tables fitting your query specifics and combines them into a table.
A UNION statement effectively does a SELECT DISTINCT on the results set. If you know that all the records returned are unique from your union, use UNION ALL instead, it gives faster results.
60.   Select employee details from employee table if data exists in incentive table ?
select * from EMPLOYEE where EMPLOYEE_ID IN(select DISTINCT(EMPLOYEE_RFF_ID) from INCENTIVE)

 
61.   How to fetch data that are common in two query results?
SELECT * FROM EMPLOYEE  INTERSECT SELECT TOP 4 * FROM EMPLOYEE

62.   Get Employee ID's of those employees who didn't receive incentives
select * from EMPLOYEE where EMPLOYEE_ID NOT IN(select DISTINCT(EMPLOYEE_RFF_ID) from INCENTIVE)
63.   Select 20 % of salary from John , 10% of Salary for Roy and for other 15 % of salary from employee table
SELECT EMP.FIRST_NAME,(CASE EMP.FIRST_NAME WHEN 'JOHN' THEN EMP.SALARY *.20 WHEN 'ROY' THEN EMP.SALARY *.10 ELSE EMP.SALARY *.15 END) AS SALARY FROM EMPLOYEE EMP
64.   Select Banking as 'Bank Dept', Insurance as 'Insurance Dept' and Services as 'Services Dept' from employee table
SELECT (CASE DEPARTMENT WHEN 'BANKING' THEN 'BANK DEPT' WHEN 'INSURANCE' THEN 'INSURANCE DEPT' WHEN 'SERVICES' THEN 'SERVICES DEPT' END)AS DEPARTMENT  FROM EMPLOYEE
65.   Delete employee data from employee table who got incentives in incentive table
DELETE FROM EMPLOYEE WHERE EMPLOYEE_ID IN (SELECT EMPLOYEE_RFF_ID FROM INCENTIVE)
66.   Insert into employee table Last Name with " ' " (Single Quote - Special Character)
INSERT INTO EMPLOYEE(FIRST_NAME,LAST_NAME,SALARY,JOINING_DATE,DEPARTMENT)
VALUES('SAM','DEEN''',750000,'2-2-2013','BANKING')
67.   Select Last Name from employee table which contain only numbers
SELECT LAST_NAME FROM EMPLOYEE WHERE LAST_NAME NOT LIKE '%[^0-9]%'
68.   Write a query to rank employees based on their incentives for a month
SELECT EMP.FIRST_NAME,INS.INCENTIVE_AMOUNT,RANK() OVER(ORDER BY INS.INCENTIVE_AMOUNT DESC) AS RANK FROM EMPLOYEE EMP INNER JOIN INCENTIVE INS ON EMP.EMPLOYEE_ID=INS.EMPLOYEE_RFF_ID
Posted by at No comments:
Labels: , , , ,
Subscribe to: Posts (Atom)