A boolean value should only contain two values, True or False, but is it correct? Usually people assume so, but sometimes miss the fact that there could be the absence of the value all-together. In databases this is absence is usually stored as NULL and this blog showcases how to find them, use them properly and 11 lessons to learn to be a NULL Pro!

Keep in mind, it’s not only booleans that can contain NULL values, it’s all the columns where you don’t define a NOT NULL constraint!