If you have multiple databases and you want to perform the operation in the database then firstly select database after that you can perform the operation.
Syntax:-
USE databaseName
Now, firstly check the all database through below command
SHOW DATABASES;
Output:-
+--------------------+ | Database | +--------------------+ | information_schema | | email_archive | | flood | | employee_system | | performance_schema |
Now, you want to work in employee_system then use below command
Example:-
USE employee_system;