📘 SQL Blog Series – 5

 Today, we’re going to understand how to use aggregrate fucntions in Sql.

An aggregate function is a function that performs a calculation on a set of values, and returns a single value.

Aggregate functions are often used with the GROUP BY clause of the SELECT statement. The GROUP BY clause splits the result-set into groups of values and the aggregate function can be used to return a single value for each group.

The most commonly used SQL aggregate functions are:

• MIN() - returns the smallest value within the selected column
• MAX() - returns the largest value within the selected column
• COUNT() - returns the number of rows in a set
• SUM() - returns the total sum of a numerical column
• AVG() - returns the average value of a numerical column

Aggregate functions ignore null values (except for COUNT(*)).

We will go through the aggregate functions above in the next chapters.

The SQL MIN() and MAX() Functions

The MIN() function returns the smallest value of the selected column.

Example: This is like our python min method which is used the fetch the small value from a set of values.

The MAX() function returns the largest value of the selected column.

Example: This is like our python max method which is used the fetch the largest from a set of values.

The output of both these are always single it fecthes minimum values or maximum value from a set of valeus.

The SQL COUNT() Function

The COUNT() function returns the number of rows that matches a specified criterion.

Example: The count is method is like the len function in our python .

The SQL SUM() Function

The SUM() function returns the total sum of a numeric column.

The SQL AVG() Function

The AVG() function returns the average value of a numeric column.

In the next Blog we are going to be see how they are used to filter the data from the database tables.The SQL Aggregate Functions plays a crucial role for both modifying the data or filtering the data in sql.So these are some of the essential fucntions to know about how to peform some operations on data.