In today’s article, we will be explaining what NOT NULL is and how to use it, which is the opposite of IS NULL in PostgreSQL.
Unlike NOT NULL, IS NULL means not fetching NULL columns in the table.
First, let’s view our data by selecting from our students table.
As you can see, the vize value of our last record appears to be NULL.
As seen above, when we use != (not equal) the result will not be returned.
This is because equalization, addition and subtraction cannot be performed using a NULL value.
Its correct usage is as follows.
