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.