“In Part 1 of this series, I will cover how to use the five most
common and basic aggregate functions on PostgreSQL. Those functions
are count(), min(), max(), avg(), and sum(). Look for more fun with
aggregates and operators later in this series of articles.”
“An aggregate function is a function such as count() or
sum() that you can use to calculate totals. In writing expressions
and in programming, you can use SQL aggregate functions to
determine various statistics and values. Aggregate functions can
greatly reduce the amount of coding that you need to do in order to
get information from your database.“