MySQL COUNT(), AVG() and SUM() Functions

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The COUNT() function returns the number of rows that matches a specified criterion.

				
					COUNT() Syntax

SELECT COUNT(column_name)
FROM table_name
WHERE condition;

				
					The AVG() function returns the average value of a numeric column. 

AVG() Syntax
SELECT AVG(column_name)
FROM table_name
WHERE condition;

				
					The SUM() function returns the total sum of a numeric column. 

SUM() Syntax
SELECT SUM(column_name)
FROM table_name
WHERE condition;

COUNT() Example

The following SQL statement finds the number of products:

				
					SELECT COUNT(ProductID)
FROM Products;

The following SQL statement finds the average price of all products:

				
					SELECT AVG(Price)
FROM Products;

The following SQL statement finds the sum of the “Quantity” fields in the “OrderDetails” table:

				
					SELECT SUM(Quantity)
FROM OrderDetails;