有时候你在操作数据库的时候数据库出问题了，而你又要把数据库drop时就出问题了：Cannot drop database "databasename" because it is currently in use.
这时你只要按照以下方法做就可以了：
use master
go
alter database databasename set single_user with rollback immediate
go
drop database databasename
go
或者是：
use master
alter database databasename set single_user with rollback immediate
drop database databasename