Let's say we want to display the name and grade of all the students. However, for the students who don't have grade information, we want to display 'No Grade' instead of it left blank.
One way of doing this would be using a conditional CASE clause.
However, when the use case is simply to implement a check of a value being NULL, there is a cleaner way. We can use an IFNULL function to do this.
IFNULL accepts 2 arguments. The first argument is the column that needs to be picked (in this case, grade). The second argument is the value that is supposed to be returned in case the value from the column picked turns out to be NULL.