SQL Aggregation Function | COUNT(*), COUNT(1), COUNT(Col_Name) - The Difference That Breaks Queries

Published: 23 March 2026
on channel: Data Guy

Description:

Stop just looking at rows and start finding the story in your data! 📊 In this video of our SQL Tutorial series, we dive deep into SQL Aggregation Functions.

Learn how to use:

COUNT(): How to count rows and specific values.

SUM(): Totaling up numeric columns.

AVG(): Finding the mean value easily.

MIN() & MAX(): Identifying the range of your data.

We’ll also touch on why these functions are almost always used with the GROUP BY clause to generate meaningful reports. Whether you're a beginner or refreshing your skills for a data interview, this guide has you covered.

Today we will learn five essential aggregate functions, including how to use COUNT SQL based on different criteria. This video also details the differences between COUNT(*), COUNT(1), and COUNT(Column_Name), demonstrating how each function counts rows based on different criteria, including handling of NULL values, which is key for any aspiring data analyst.

👨‍💻 About Data Guy:
On this channel, I simplify complex data engineering and data analysis concepts. Whether you are a student or a professional, I’m here to help you master the world of data.

📚 Catch Up on the SQL Tutorial Series:
If you are new here, make sure to watch the previous videos in order to follow along with the Farmers Market Dataset:
Dataset Link : https://github.com/skillmasters45-bee...

Video 1: Introduction to Databases
📺 Watch here:    • Introduction to Databases | SQL Tutorial S...

Video 2: Database Design (Primary/Foreign Keys & Schemas)
📺 Watch here:    • Database Design - Primary and Foreign Keys...

Video 3: MySQL Workbench Installation (Windows)
📺 Watch here:    • STOP Installing MYSQL Workbench Wrong! EXP...

Video 4: How to Import the Farmers Market Dataset
📺 Watch here:    • How to import dataset into MySQL Workbench...

Video 5: Mastering SELECT, ORDER BY, LIMIT, and OFFSET
📺 Watch here:    • Mastering the SQL SELECT Statement: ORDER ...

Video 6: Filter Data Like a Pro with the WHERE Clause
📺 Watch here:    • FILTER Your Data LIKE A PRO with SQL WHERE...

Video 7 : DISTINCT and ISNULL
📺 Watch here:    • Two SQL Keywords That Change Everything | ...

Video 8 : CASE and IF Statement
📺 Watch here:    • CASE Statement in SQL | Transform Raw Data...

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