What are prices of each catalog entry id?
select catalog_entry_id, price_in_dollars, price_in_euros, price_in_pounds from catalog_contents
Show me only the prices in USD!
select catalog_entry_id, price_in_dollars from catalog_contents
Which are the contents of the catalog with the highest one?
select * from catalog_contents order by price_in_dollars desc limit 1
What is its entry name?
select catalog_entry_name from catalog_contents order by price_in_dollars desc limit 1