Knowledge in What is a NULL Value?

What is a NULL Value?

What is a NULL Value? A field with a NULL value is a field with no value. If a field in a table is optional, it is possible to insert a new record or update a record without adding a value to this field. Then, the field will be saved with a NULL value. Note: A NULL value is different from a zero value or a field that contains spaces. A field with a NULL value is one that has been left blank during record creation! ________________________________________ How to Test for NULL Values? It is not possible to test for NULL values with comparison operators, such as =,