ISNULL Function


I found out there is a huge difference between using ISNULL(table.column) = 1 and different type of writing this formula (table.column) IS NULL. Do you have know from where this difference comes from ?

Here is example from analysis:



Hi the only difference between the two PQL statements ISNULL() and IS NULL should be that ISNULL() returns an integer value (either 0 or 1), while IS NULL returns a boolean value (either true or false), stating if the field is empty.

I tried using ISNULL() = 1 and IS NULL interchangeable and couldn’t reproduce any differences of the result.