EDUCBA

EDUCBA

MENUMENU
  • Blog
  • Free Courses
  • All Courses
  • All in One Bundle
  • Login
Home Data Science Data Science Tutorials SQL Tutorial Aggregate Functions in SQL

Aggregate Functions in SQL

Priya Pedamkar
Article byPriya Pedamkar

Updated March 27, 2023

Aggregate Functions in SQL

Introduction to Aggregate Functions in SQL

Aggregate functions in SQL are used for performing calculations on an entire column(which could have thousands of rows). They are generally used for summarizing large datasets. If you are familiar with Excel, then these functions are similar to the ones which we have in Excel.

Start Your Free Data Science Course

Hadoop, Data Science, Statistics & others

Syntax:

The generic syntax for AGGREGATE functions is as follows:

SELECT AGGREGATE_FUNCTION (column_name)
FROM table_name
WHERE condition;

Parameters:

The different parameters used in the syntax are:

  • AGGREGATE_FUNCTION: Mention the type of aggregation function you want to use from { SUM, COUNT, MIN, MAX, AVG }.
  • column_name: Mention the column name for which you want to perform COUNT operation.
  • FROM table_name: Mention the table name from which the column has to be fetched.
  • WHERE condition: Mention the specific criteria for filtering the data i.e. the criteria you want the output record to meet.

Above all the mentioned parameters except the WHERE condition are mandatory. You may use GROUP BY, HAVING and ORDER BY clauses based on your requirement.

Going ahead we will be discussing the above-mentioned functions in great detail.

In order to demonstrate and explain the aggregate functions in SQL effectively, we will be using the following table. It is a sample “customers” table of an online stationery store that contains 15 records with each customer’s id, name, city, the country he/she belongs to, Items purchased by him/her and the amount_paid by them.

The schema for the “customers” table is as follows:

Number of records: 15

Customers
ID(primary key)
Customer
City
Country
Items_purchased
Amount_paid

Let’s have a look at the records in the customer’s table. So that later, we can understand how aggregate functions are helpful in calculations.

ID Customer City Country Items_purchased Amount_paid
1 Peter King Manchester England Books 120
2 Priya Krishna New Delhi India pen 50
3 Jim Halpert Manchester England pencil 43
4 Michael Scott New York USA Books 250
5 Harvey Specter Birmingham England pencil 100
6 Deepa Kamat Mumbai India Books 370
7 Anita Desai London England pencil 50
8 Rachel Zane Michigan USA pen 70
9 Pretoria John Canberra Australia pen 190
10 John L Budapest Hungry Books 540
11 Justin Green Ottawa City Canada pen 65
12 Babita Ghosh Kolkata India pencil 75
13 Krish Pratt London England eraser 30
14 Elizabeth Blunt London England pencil 340
15 Nina Debrov Amsterdam Netherlands Books 452
NULL NULL NULL NULL NULL NULL

SQL Aggregate Functions

The SQL aggregate functions are:

  • COUNT
  • SUM
  • MIN / MAX
  • AVG

1. COUNT FUNCTION

The COUNT function is used to count the total number of values or records stored in a specified column. It can be customized further by specifying criteria.

Here is an example to illustrate the use of COUNT Function.

Example #1

Find out the number of customers who are from England.

SELECT COUNT(Customer)FROM Customers WHERE Country = 'England';

–We can even give a name to the output column

SELECT COUNT(Customer) as "No of customers from England" FROM Customers WHERE Country = 'England';

Output:

Aggregate Function in SQL- Count Fumction

Note: we should keep in mind that all aggregate functions exclude NULL values before operating on the column.

If you want to consider duplicates and NULL values in your result, then you may use a specialized version of COUNT, ie. COUNT(*).COUNT(*) returns all the records from a column including the NULL and duplicate values.

2. SUM FUNCTION

Sum function is used to calculate the sum of all the values present in a particular column. Unlike count, it works only on numeric data fields only. For customization, you may also specify criteria.

Here are a few examples to illustrate the SUM function.

Example #2

Find the total of money spent by customers from India.

SELECT SUM(Amount_paid)FROM Customers WHERE Country = 'India';

SUM FUNCTION

Example #3

Find the total revenue collected along with different categories of stationery items.

SELECT Items_purchased as "Category", SUM(Amount_paid) as "Revenue_generated"
FROM Customers
GROUP BY Items_purchased;

SUM FUNCTION

3. MIN/MAX FUNCTION

MIN function is used to return the lowest value in a particular column. Whereas MAX function is used to find out the highest value in a particular column.

Here are a few examples to illustrate the use of MIN/MAX functions.

Example #4

Find out the min price of a stationary item.

SELECT MIN(Amount_paid) FROM Customers;

MIN/MAX FUNCTION

Example #5

Find out the max price of a stationary item.

SELECT MAX(Amount_paid) FROM Customers;

max price

Example #6

Find the min and max values of stationery items along with different categories.

SELECT Items_purchased as "Category", MIN(Amount_paid) as "Minimum Amount", MAX(Amount_paid) as "Minimum Amount"
FROM Customers
GROUP BY Items_purchased
ORDER BY Items_purchased;

min and max values

4. AVG FUNCTION

AVG function is used to calculate the average value of all the records present in the selected column. When calculating the average, the AVG function completely ignores NULL values.

Here are a few examples to illustrate the usage of the AVG function.

Example #7

Find the average price of the stationery item.

SELECT AVG(Amount_paid)FROM Customers;

Output:

Aggregate Functions in SQL - AVG Function

Example #8

Find the average revenue generated by different categories of stationery items, ordered by the average revenue in ascending order.

SELECT Items_purchased as "Category", AVG(Amount_paid) as "Average Revenue"
FROM Customers
GROUP BY Items_purchased
ORDER BY 2;

–We can simply use the column number in the group by or order by clause for the simplicity of code.

Output:

Aggregate Functions in SQL

Some limitations of SQL Aggregate Functions

  • All aggregate functions exclude NULL values before operating on the column
  • All aggregate functions, except COUNT, works only on numeric data values

Conclusion

So in this article, we have learned about SQL aggregate functions which are very useful in calculating, summarizing and understanding the patterns in a huge dataset.

Recommended Articles

We hope that this EDUCBA information on “Aggregate Functions in SQL” was beneficial to you. You can view EDUCBA’s recommended articles for more information.

  1. Cursor in MySQL
  2. MySQL Aggregate Function
  3. SQL Keywords
  4. SQL Clauses
All in One Excel VBA Bundle
500+ Hours of HD Videos
15 Learning Paths
120+ Courses
Verifiable Certificate of Completion
Lifetime Access
Financial Analyst Masters Training Program
2000+ Hours of HD Videos
43 Learning Paths
550+ Courses
Verifiable Certificate of Completion
Lifetime Access
All in One Data Science Bundle
2000+ Hour of HD Videos
80 Learning Paths
400+ Courses
Verifiable Certificate of Completion
Lifetime Access
All in One Software Development Bundle
5000+ Hours of HD Videos
149 Learning Paths
1050+ Courses
Verifiable Certificate of Completion
Lifetime Access
Primary Sidebar
All in One Data Science Bundle2000+ Hour of HD Videos | 80 Learning Paths | 400+ Courses | Verifiable Certificate of Completion | Lifetime Access
Financial Analyst Masters Training Program2000+ Hours of HD Videos | 43 Learning Paths | 550+ Courses | Verifiable Certificate of Completion | Lifetime Access
Footer
About Us
  • Blog
  • Who is EDUCBA?
  • Sign Up
  • Live Classes
  • Certificate from Top Institutions
  • Contact Us
  • Verifiable Certificate
  • Reviews
  • Terms and Conditions
  • Privacy Policy
  •  
Apps
  • iPhone & iPad
  • Android
Resources
  • Free Courses
  • Database Management
  • Machine Learning
  • All Tutorials
Certification Courses
  • All Courses
  • Data Science Course - All in One Bundle
  • Machine Learning Course
  • Hadoop Certification Training
  • Cloud Computing Training Course
  • R Programming Course
  • AWS Training Course
  • SAS Training Course

ISO 10004:2018 & ISO 9001:2015 Certified

© 2023 - EDUCBA. ALL RIGHTS RESERVED. THE CERTIFICATION NAMES ARE THE TRADEMARKS OF THEIR RESPECTIVE OWNERS.

Let’s Get Started

By signing up, you agree to our Terms of Use and Privacy Policy.

EDUCBA

*Please provide your correct email id. Login details for this Free course will be emailed to you

EDUCBA
Free Data Science Course

Hadoop, Data Science, Statistics & others

By continuing above step, you agree to our Terms of Use and Privacy Policy.
*Please provide your correct email id. Login details for this Free course will be emailed to you

EDUCBA

*Please provide your correct email id. Login details for this Free course will be emailed to you
EDUCBA

*Please provide your correct email id. Login details for this Free course will be emailed to you
EDUCBA Login

Forgot Password?

By signing up, you agree to our Terms of Use and Privacy Policy.

This website or its third-party tools use cookies, which are necessary to its functioning and required to achieve the purposes illustrated in the cookie policy. By closing this banner, scrolling this page, clicking a link or continuing to browse otherwise, you agree to our Privacy Policy

Loading . . .
Quiz
Question:

Answer:

Quiz Result
Total QuestionsCorrect AnswersWrong AnswersPercentage

Explore 1000+ varieties of Mock tests View more