To answer this question, you need to understand how views work in a database. Let's go through each option to understand why it is correct or incorrect:
Option A) The underlying tables must have data - This option is incorrect because the existence of data in the underlying tables is not necessary for the query on a view to execute successfully. The view is a virtual table that is derived from one or more underlying tables, and it does not depend on the presence of data in those tables.
Option B) You need SELECT privileges on the view - This option is correct because in order to execute a query on an existing view, you need to have SELECT privileges specifically on that view. Privileges on the underlying tables are not sufficient; you need to have the necessary privileges on the view itself.
Option C) The underlying tables must be in the same schema - This option is incorrect because the underlying tables of a view can be in different schemas. The schema of the view itself is independent of the schemas of the underlying tables.
Option D) You need SELECT privileges only on the underlying tables - This option is incorrect because, as mentioned earlier, you need SELECT privileges on the view itself, not just on the underlying tables. Privileges on the underlying tables alone are not enough to execute a query on a view.
The correct answer is Option B. This option is correct because you need SELECT privileges on the view in order to execute a query on it successfully.