STDDEV_SAMP() function in MySQL is used to calculate sample standard deviation of an expression.
Syntax :
STDDEV_SAMP(expr);
Parameter : This method accepts only one parameter.
- expr : Input expression from which we want to calculate sample standard deviation.
Returns : It returns the population standard deviation.
Example-1 :
Finding sample standard deviation of RunScored column from the given Player table using STDDEV_SAMP Function.
Creating a Player table :
CREATE TABLE Player ( PlayerId INT AUTO_INCREMENT, PlayerName VARCHAR(100) NOT NULL, RunScored INT NOT NULL, WicketsTaken INT NOT NULL, PRIMARY KEY(PlayerId) );
Inserting data into the Table :
INSERT INTO Player (PlayerName, RunScored, WicketsTaken ) VALUES ('KL Rahul', 52, 0 ), ('Hardik Pandya', 30, 1 ), ('Ravindra Jadeja', 18, 2 ), ('Washington Sundar', 10, 1), ('D Chahar', 11, 2 ), ('Mitchell Starc', 0, 3);
To verify used the following command as follows.
SELECT * from Player ;
Output :
PLAYERID | PLAYERNAME | RUNSCORED | WICKETSTAKEN |
---|---|---|---|
1 | KL Rahul | 52 | 0 |
2 | Hardik Pandya | 30 | 1 |
3 | Ravindra Jadeja | 18 | 2 |
4 | Washington Sundar | 10 | 1 |
5 | D Chahar | 11 | 2 |
6 | Mitchell Starc | 0 | 3 |
Now we are going to find sample standard deviation for RunScored column.
SELECT STDDEV_SAMP(RunScored ) as Samp_Standard_Deviation FROM Player ;
Output :
SAMP_STANDARD_DEVIATION |
---|
18.486932321687846 |
Example-2 :
Now we are going to find sample standard deviation of WicketsTaken column.
SELECT STDDEV_SAMP(WicketsTaken) as Samp_Std_Dev_Wickets FROM Player ;
Output :
SAMP_STD_DEV_WICKETS |
---|
1.0488088481701516 |
Example-3 :
In this example we are going to find the sample standard deviation of Income of Employee who are working in the company ‘ABC Corp.’ To demonstrate create a table named EmloyeeDetails.
CREATE TABLE EmployeeDetails( Employee_Id INT AUTO_INCREMENT, Employee_Name VARCHAR(100) NOT NULL, Working_At VARCHAR(20) NOT NULL, Work_Location VARCHAR(20) NOT NULL, Joining_Date DATE NOT NULL, Annual_Income INT NOT NULL, PRIMARY KEY(Employee_Id ) );
Inserting data into the Table :
INSERT INTO EmployeeDetails(Employee_Name, Working_At, Work_Location, Joining_Date, Annual_Income ) VALUES ('Amit Khan', 'XYZ Digital', 'Kolkata', '2019-10-06', 350000 ), ('Shreetama Pal', 'ABC Corp.', 'Kolkata', '2018-12-16', 500000 ), ('Aniket Sharma', 'PQR Soln.', 'Delhi', '2020-01-11', 300000 ), ('Maitree Jana', 'XYZ Digital', 'Kolkata', '2019-05-01', 400000 ), ('Priyanka Ojha', 'ABC Corp.', 'Delhi', '2019-02-13', 350000 ), ('Sayani Mitra', 'XYZ Digital', 'Kolkata', '2019-09-15', 320000 ), ('Nitin Dey', 'PQR Soln.', 'Delhi', '2019-10-06', 250000 ), ('Sujata Samanta', 'PQR Soln.', 'Kolkata', '2020-10-06', 350000 ), ('Sudip Majhi', 'ABC Corp.', 'Delhi', '2018-10-30', 600000 ), ('Sanjoy Kohli', 'XYZ Digital', 'Delhi', '2019-04-18', 450000 ) ;
To verify used the following command as follows.
Select * FROM EmployeeDetails;
Output :
EMPLOYEE_ID | EMPLOYEE_NAME | WORKING_AT | WORK_LOCATION | JOINING_DATE | ANNUAL_INCOME |
---|---|---|---|---|---|
1 | Amit Khan | XYZ Digital | Kolkata | 2019-10-06 | 350000 |
2 | Shreetama Pal | ABC Corp. | Kolkata | 2018-12-16 | 500000 |
3 | Aniket Sharma | PQR Soln. | Delhi | 2020-01-11 | 300000 |
4 | Maitree Jana | XYZ Digital | Kolkata | 2019-05-01 | 400000 |
5 | Priyanka Ojha | ABC Corp. | Delhi | 2019-02-13 | 350000 |
6 | Sayani Mitra | XYZ Digital | Kolkata | 2019-09-15 | 320000 |
7 | Nitin Dey | PQR Soln. | Delhi | 2019-10-06 | 250000 |
8 | Sujata Samanta | PQR Soln. | Kolkata | 2020-10-06 | 350000 |
9 | Sudip Majhi | ABC Corp. | Delhi | 2018-10-30 | 600000 |
10 | Sanjoy Kohli | XYZ Digital | Delhi | 2019-04-18 | 450000 |
Now we are going to find population standard deviation of annual Income for those Employee who are working in ‘ABC Corp.’
SELECT 'ABC Corp.' AS 'Company_Name', STDDEV_SAMP(Annual_Income) as StdDevOfAnnualIncome FROM EmployeeDetails where WORKING_AT = 'ABC Corp.';
Output :
COMPANY_NAME | STDDEVOFANNUALINCOME |
---|---|
ABC Corp. | 125830.57392117917 |