Challenge: Understanding Nulls
Explore the treatment of null values in SQL by learning to query using three-valued logic. Understand how to detect nulls with the is null operator and count non-null salary records in an Employee table, improving your ability to manage missing data in PostgreSQL.
We'll cover the following...
We'll cover the following...
Problem statement
In this challenge, you will complete two tasks to test your knowledge and understanding of null in SQL.
Task 1
Programming languages come with a special value for null values. SQL deals with such values differently than other languages because it provides a three-valued logic for nulls. Let’s check the behavior of null with the values true, false ...