In computer science, an aggregate function is a function where the values of multiple rows are grouped together as input on certain criteria to form a single value of more significant meaning or measurement such as a set, a bag or a list.

Common aggregate functions include:^[1]

• Average()
• Count()
• Maximum()
• Median()
• Minimum()
• Mode()
• Sum()

Aggregate functions are common in numerous programming languages such as Ruby, in spreadsheets, and in relational algebra.

SQL Aggregate Functions

SQL aggregate functions return a single value, calculated from values in a column.^[2]

Useful aggregate functions:

   * AVG() - Returns the average value    * COUNT() - Returns the number of rows    * FIRST() - Returns the first value    * LAST() - Returns the last value    * MAX() - Returns the largest value    * MIN() - Returns the smallest value    * SUM() - Returns the sum  

See also

• Fold (higher-order function)
• Group by (SQL), SQL implementation

References

1. ↑
2. ↑