In Php What is the difference between null and empty?

Question

Also, tell me the difference between them.I know about empty() function(It will used to check whether the variable is empty or not).I wonder to know what's the main use for is_null() function.

Answer 1

Null is a special placeholder value in the programming language that literally means "nothing". It's not 0, it's not an empty string, it's nothing. There is no value in memory being pointed to. An empty string, on the other hand, is still a string object, just a very short one.