ERROR occured for creating table

Hi King!
Thanks for reaching out.

This error is because you did not choose a DB to work with. To work with that DB you should use the following code before your queries:

USE DB_name;

or just double-clicking on the DB you would like to work with. It should become bolded in your Schemas. Once you do this you do not need to execute the query USE sales;. It is just necessary to check if the name of the DB you would like to work is bolded (for example: sales).

Hope this helps.
Best,
Tsvetelin