mssql_select_db() sets the current active database on the server that's associated with the specified link identifier.
Every subsequent call to mssql_query() will be made on the active database.
The database name.
To escape the name of a database that contains spaces, hyphens ("-"), or any other exceptional characters, the database name must be enclosed in brackets, as is shown in the example, below. This technique must also be applied when selecting a database name that is also a reserved word (such as primary).
If no link identifier is specified, the last opened link is assumed. If no link is open, the function will try to establish a link as if mssql_connect() was called, and use it.