Introduction to MySQL aggregate functions An aggregate function performs a calculation on multiple values and returns a single value. For example, you can use the AVG() aggregate function that takes ...

-- MySQL's aggregate function is used to perform calculations on multiple values and return the result in a single value like -- the average of all values, the sum of all values, and maximum & minimum ...

If you have an aggregation function (sum, avg, count) in your select clause or if you have a group by clause, all of your columns must be aggregated or grouped.<BR><BR>In the version of SQL that I ...