Differences between static and self in PHP

Differences between static and self in PHP classA {??? Publicstaticfunctionwho (){?????? Echo _ CLASS __;???}??? Publicstaticfunctiontest (){?????? Self: differences between static and self in who () PHP

Class {
??? Public static function who (){
??? ??? Echo _ CLASS __;
??? }
??? Public static function test (){
??? ??? Self: who ();
//??? ??? Static: who ();
??? }
}
A: test ();

Class B extends {
??? Public static function who (){
??? ??? Echo _ CLASS __;
??? }
}
Echo B: test ();

?

If you use the keyword self to run the result :?? A

If you use the keyword static run result: A B

Static: the parent class accesses the static method of the subclass.

Self: internal class pointer, pointing to this class, static method, attribute