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The GROUP BY statement groups rows that have the same values into summary rows, like "find the number of customers in each country".

The GROUP BY statement is often used with aggregate functions (COUNT, MAX, MIN, SUM, AVG) to group the result-set by one or more columns.

Syntax:

SELECT column_name(s)
FROM table_name
WHERE condition
GROUP BY column_name(s)
ORDER BY column_name(s);

Prerequisite Codes

If you don't have table please create below table and practice it.

My database name is SQLExamples

USE SQLExamples

Create this below Employee table

DROP TABLE Employee
CREATE TABLE Employee(
EmpId INT,
EmpName VARCHAR(25),
EmpAddress VARCHAR(100),
EmpDept VARCHAR(25)
)

Insert data inside table

INSERT INTO Employee VALUES
(1, 'Rambo', 'Kolkata', 'IT'),
(2, 'Rohit', 'Kolkata', 'IT'),
(3, 'Rohon', 'Kolkata', 'ITIS'),
(4, 'Ronok', 'Kolkata', 'ITIS'),
(5, 'Rubin', 'Kolkata', 'ITIS'),
(6, 'Sorif', 'Kolkata', 'ADMIN'),
(7, 'Soriful', 'Kolkata', 'ADMIN'),
(8, 'Sofik', 'Kolkata', 'ADMIN')

SELECT * FROM Employee

Output:

The above code will produce the following result-

EmpId	EmpName	EmpAddress	EmpDept
1	Rambo	Kolkata	IT
2	Rohit	Kolkata	IT
3	Rohon	Kolkata	ITIS
4	Ronok	Kolkata	ITIS
5	Rubin	Kolkata	ITIS
6	Sorif	Kolkata	ADMIN
7	Soriful	Kolkata	ADMIN
8	Sofik	Kolkata	ADMIN

Example 1: SQL GROUP BY

Code:

SELECT EmpDept, COUNT(EmpDept) AS DeptCount 
FROM Employee
GROUP BY EmpDept 

Output:

The above code will produce the following result-

EmpDept	DeptCount
ADMIN	3
IT	2
ITIS	3

Example:

Code:

SELECT EmpDept, COUNT(EmpDept) AS DeptCount 
FROM Employee
GROUP BY EmpDept 
ORDER BY EmpDept DESC

Output:

The above code will produce the following result-

EmpDept	DeptCount
ITIS	3
IT	2
ADMIN	3

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