> There are 3 people, and there are 3 people who don't have a NULL car. This is not what you are asking with your query: as someone else stated, NULL is meant

> There are 3 people, and there are 3 people who don't have a NULL car. This is not what you are asking with your query: as someone else stated, NULL is meant to be "UNKNOWN", or "it could be any valid value". So nothing is ever equal to something that can be anything, because even another NULL (i.e. unknown) value is in general different. So in the line SELECT name FROM people WHERE carId = NULL the condition will always be false. Now if instead if meant to search for the rows where carId is actually unknown you have to write SELECT name FROM people WHERE carId is NULL And your query will return as one may expect 2.