PHP TutorialsPhp What is
PHP INI TutorialsPhp ini What is
Null means "nothing" or "no value" . The special cases NULL should never be enclosed in quotes unless you want to treat them as genuine text (or strings). which is that they are case-insensitive. When a column is assigned the NULL attribute, it is possible for the field to remain empty regardless of whether the other row fields have been populated.
In the above examle $Store_null variable is stored NULL values.