Selecting a Database
When you first connect to MySQL, you do not have any databases open for use. Before you can perform any database operations, you need to select a database. To do this you use the USE keyword.
For example, to use the crashcourse database you would enter the following:
The USE statement does not return any results. Depending on the client used, some form of notification might be displayed. For example, the Database changed message shown here is displayed by the mysql command-line utility upon successful database selection.
Remember, you must always USE a database before you can access any data in it.