SQL Aggregate Functions

Jun 23, 2026Aditya948351

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An aggregate function is a function that performs a calculation on a set of values, and returns a single value. These functions are commonly used with the GROUP BY clause in SQL to group rows that share a common attribute.

The most commonly used SQL aggregate functions are:

• MIN() - returns the smallest value within the selected column
• MAX() - returns the largest value within the selected column
• COUNT() - returns the number of rows in a set
• SUM() - returns the total sum of a numerical column
• AVG() - returns the average value of a numerical column

Aggregate functions ignore null values (except for COUNT()).

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Demo Database

Below is a selection from the Products table used in the examples:

ProductID	ProductName	SupplierID	CategoryID	Unit	Price
1	Chais	1	1	10 boxes x 20 bags	18
2	Chang	1	1	24 - 12 oz bottles	19
3	Aniseed Syrup	1	2	12 - 550 ml bottles	10
4	Chef Anton's Cajun Seasoning	2	2	48 - 6 oz jars	22
5	Chef Anton's Gumbo Mix	2	2	36 boxes	21.35

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Common SQL Aggregate Functions

MIN() and MAX()

• Description: The MIN() function returns the smallest value of the selected column. The MAX() function returns the largest value of the selected column.
• Syntax:

  SELECT MIN(column_name) FROM table_name WHERE condition;
  SELECT MAX(column_name) FROM table_name WHERE condition;

• Example (MIN): Find the lowest price in the Price column:

  SELECT MIN(Price) FROM Products;

• Example (MAX): Find the highest price in the Price column:

  SELECT MAX(Price) FROM Products;

COUNT()

• Description: Returns the number of rows in a set.
• Syntax:
  • COUNT(column_name) — Counts non-null values in the specified column
  • COUNT(*) — Counts all rows
• Example: Count the total number of products:

  SELECT COUNT(*) FROM Products;

SUM()

• Description: Returns the total sum of a numerical column.
• Syntax: SUM(column_name)
• Example: Find the sum of all prices in the Products table:

  SELECT SUM(Price) FROM Products;

AVG()

• Description: Returns the average value of a numerical column.
• Syntax: AVG(column_name)
• Example: Find the average price of all products:

  SELECT AVG(Price) FROM Products;

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Set Column Name (Alias)

When you use aggregate functions, the returned column will not have a descriptive name. To give the column a descriptive name, use the AS keyword (alias):

Example

SELECT MIN(Price) AS SmallestPrice FROM Products;

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Using Aggregate Functions with GROUP BY

Aggregate functions are often combined with the GROUP BY clause to group rows that have the same values in specified columns.

Syntax

SELECT column1, AGGREGATE_FUNCTION(column2)
FROM table_name
GROUP BY column1;

Example

Here we use the MIN() function and the GROUP BY clause to return the smallest price for each category in the Products table:

SELECT MIN(Price) AS SmallestPrice, CategoryID  
FROM Products  
GROUP BY CategoryID;