SQL Aggregate functions determine and calculate values from multiple columns in a table and return a single value.
There are 7 aggregate functions in SQL :
AVG() : Returns the average value from specified columns.
COUNT() : Returns number of table rows.
MAX() : Returns the largest value among the records.
MIN() : Returns smallest value among the records.
SUM() : Returns the sum of specified column values.
FIRST() : Returns the first value.
LAST() : Returns last value.
