CounterID	UInt32					
dummy	String					
StartDate	Date					
Sign	Int8					
VisitID	UInt64					
UserID	UInt64					
StartTime	DateTime					
ClickLogID	UInt64					
1	Hello, Alter Table!
CounterID	UInt32					
StartDate	Date					
Sign	Int8					
VisitID	UInt64					
UserID	UInt64					
StartTime	DateTime					
ClickLogID	UInt64