连接两列，合并列中的显示变为空

I have a query that I am going to use in one of my stored procs. Specs dictate that, in the table, there should are 3 parts of an address, but there are going to be merged into one column: AddressLine1 which is the Street, AddressLine2 which is the Subdivision/, and AddressLine3 which is the City/State/Province. out of all these 3 fields, only AddressLine1 is mandatory, the other 2 can be left NULL. here is my code joining the 3 address fields into one:I have a query that I am going to use in one of