An aggregate function allows you to perform the calculation on a set of values to return the single scalar value. Aggregate Functions are used for performing operations on multiple rows of a particular column and result in a single value. SQL aggregate functions are inbuilt functions that are used for performing various operations in data.
Count() in SQL
count()function is used to count a total number of records in a table with a condition or without a condition.
Select count(column_name) from table_name;
Select count(Email) from customers
Select count(Amount) from customers where amount > 5000
Sum() in SQL
sum() function is used to return the submission of all numeric values in a column.
Select SUM(column_name) from table_name
Select sum(amount) from customer
Avg() in SQL
AVG() function is used to return an average value after the calculation performed in a numeric column
Select avg (column_name) from table_name
select avg(amount) from customer