Understanding the Problem and Possible Solutions

In this article, we will explore a common problem when working with databases in Python using the psycopg2 library. The problem is selecting data from a database where some of the values can be NULL. We will discuss possible solutions to this issue.

Background Information on PostgreSQL’s LIKE Operator

To understand how to solve this problem, it’s essential to know how PostgreSQL’s LIKE operator works. The LIKE operator allows us to match a string against a pattern. There are several types of patterns we can use with the LIKE operator:

• %: Matches any characters (including none) before or after the specified character.
• _: Matches exactly one character before or after the specified character.

However, these patterns cannot be used directly in our query if we want to match a value that is NULL. This is because PostgreSQL’s LIKE operator does not support NULL values on its left side when using % or _.

Last modified on 2023-11-03