This query works:
select name, UnitPrice, ProductCode, UseStandardPrice from PriceBookEntry
But this query fails with the complaint "No such column StandardPrice":
select name, UnitPrice, ProductCode, StandardPrice, UseStandardPrice from PriceBookEntry
StandardPrice is a standard field. Not one we have added.
For whatever clue it may be, I used Navatar's lister of object fields, and StandardPrice doesn't appear:
Below I'm attempting to insert a picture that shows the StandardPrice field in my PriceBookEntry description.