Flash cards
Review the key moves
What is the main idea behind SQL Aggregate Functions?
Lesson checks
Practice each idea before moving on
Short Mimo-style checks built from this lesson's code, terms, and sequence.
Which statement best captures the main point of this lesson?
Put the learning moves in the order that makes the concept easiest to apply.
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 of a column
- MAX() - returns the largest value of a column
- COUNT() - returns the number of rows in a set
- SUM() - returns the 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.