Aggregate Functions

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christian.dinh
Published Jul 30, 2021Updated Sep 9, 2021
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In SQL, aggregate functions perform a calculation on a set of values and return a single value. They are often used with the GROUP BY clause of the SELECT statement.

Note: Except for COUNT(*), aggregate functions ignore all NULL values.

Example

List all the years and their number of movies, but only the years with more than 5 movies:

SELECT year,
  COUNT(*)
FROM movies
GROUP BY year
HAVING COUNT(*) > 5;

Aggregate Functions

AVG()
Returns the average value in a column.
COUNT()
Returns the number of rows that match the specified criteria.
MAX()
Returns the largest value in a column.
MIN()
Returns the smallest value in a column.
SUM()
Returns the sum of all the value in that column.

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