Changes the database context to the specified database or database snapshot.
When a SQL Server login connects to SQL Server, the login is automatically connected to its default database and acquires the security context of a database user. If no database user has been created for the SQL Server login, the login connects as guest. If the database user does not have CONNECT permission on the database, the USE statement will fail. If no default database has been assigned to the login, its default database will be set to master.
USE is executed at both compile and execution time and takes effect immediately. Therefore, statements that appear in a batch after the USE statement are executed in the specified database.
The following example changes the database context to the AdventureWorks2012 database.
USE AdventureWorks2012; GO