The current W3Schools page explains SQL aggregate functions, which are special functions in SQL that perform calculations on a set of values and return a single value as a result. These functions are commonly used with the GROUP BY clause to group results and compute a value for each group.

The most common SQL aggregate functions are:

• MIN() — returns the smallest value in a specified column
• MAX() — returns the largest value
• COUNT() — returns the number of rows in a set
• SUM() — returns the total sum of a numeric column
• AVG() — returns the average value of a numeric column

Key points:

• Aggregate functions ignore NULL values (except for COUNT(*)).
• These functions are often used to extract summary information from a dataset, such as totals, averages, or counts, especially when combined with grouping.

The page also indicates that further chapters will discuss each function in detail.[1]

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SQL Aggregate Functions

SQL Aggregate Functions

An aggregate function is a function that performs a calculation on a set of values, and returns a single value.

Aggregate functions are often used with the GROUP BY clause of the SELECT statement. The GROUP BY clause splits the result-set into groups of values and the aggregate function can be used to return a single value for each group.

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(*)).

We will go through the aggregate functions above in the next chapters.