How to create B+ tree data structure and print left and right total child node.

See more:

PHP

MySQL

I have create only data structure i show you,
table name - classes
column name
snc, parentsclass, childclassleft, childclassright,

What I have tried:

Dear sir i have a problem i want to create binary tree my project but i not fetch all child nods in left and right please help you sir.