SQL Aggregate Functions - Aggregate Examples Tutorial

Common SQL Aggregate Functions

There are five primary aggregate functions used in SQL: COUNT, SUM, AVG, MIN, and MAX. Each serves a specific purpose in summarizing data.

• COUNT: Counts the number of rows or non-null values in a column.
• SUM: Adds up all numeric values in a column.
• AVG: Calculates the average of numeric values.
• MIN: Finds the smallest value in a column.
• MAX: Finds the largest value in a column.

Using COUNT to Count Rows

The COUNT function is used to count rows in a table or non-null values in a specific column.

It is useful for determining the number of records that meet certain criteria.

Summing Values with SUM

SUM adds all numeric values in a column, which is helpful for calculating totals like sales or salaries.

Calculating Averages with AVG

AVG computes the average value of a numeric column, useful for understanding typical values.

Finding Minimum and Maximum Values

MIN and MAX functions help identify the smallest and largest values in a column, respectively.

Combining Aggregate Functions with GROUP BY

GROUP BY allows you to apply aggregate functions to subsets of data grouped by one or more columns.

This is useful for segmenting data, such as calculating total sales per region.