How to query all the data contained in the tree menu with SQL statements
Sql Server 2000 Because you said here that there are only three levels of classification, I won't write Sql functions. I will get the classids of all subclasses below North China (excluding the classids of North China) and choose the classids from the New Class Where Class Parentid (choose the classids from the New Class with Class Parentid = 5 1).