Aggregate Functions

An aggregate function allows one perform a calculation on a set of values to return a single scalar value. Commonly used ones include:

• COUNT() => number of rows with non-empty values
• SUM() => sum of all values in a column
• MAX() / MIN()
• AVG()
• ROUND() => e.g. – ROUND(columnName, decimalPlaces)
• GROUP BY => groups identical data into groups
• HAVING => limits result of a query based on aggregate property.