A primary key is a column in a table which:
1. Has a unique value for each row (no duplicate values);
2. Cannot contain an `empty` / `null` value for any row.

A column can be marked as a primary key using the `PRIMARY KEY` keyword, inside the `CREATE` statement while creating the respective table.



This course offers an easy-to-follow introduction to the basics of SQL databases and the Structured Query Language (SQL). Through engaging video lessons and thoughtfully crafted exercises, you’ll explore essential concepts step by step. Each topic is explained in detail and paired with hands-on practice to ensure you not only understand but also retain what you’ve learned.


This section will introduce you to coding in SQL. It will start with some basic information related to SQL and SQL Databases in general, eventually moving towards writing basic SQL queries. The section also includes some fun exercises where you will get to practice the SQL syntax.


We will get an introduction to filtering data from our selections. This will give us control over what kind of data we fetch from the database. This section will cover the syntax for filtering data and various operators which can help us write robust conditions for conditional selection of data.

This section focuses on concepts related to sorting the tables based on the column values. Sorting can be useful in extracting the minimum or maximum values from a column or for making it easier to find relevant information quickly. We will also look at a keyword which can help us limit the number of rows that are fetched by our SELECT statements, making our queries more concise.

You will learn about useful queries and keywords that can help us in populating a database with some data. This will include queries for creating tables, and for inserting rows into those tables. We will also cover two additional keywords that can help us in making our tables more intractable and robust.

We will look at how to modify or delete data in an SQL database. This will include queries for updating or deleting rows in a table and making a copy of a table or deleting it.

Primary Keys

Demonstration: