Multifeature cubes allow us to construct interesting data cubes based on rather sophisticated query conditions. Can you construct the following multifeature cube by translating the following user requests into queries using the form introduced in this textbook?

a. Construct a smart shopper cube where a shopper is smart if at least \(10 \%\) of the goods she buys in each shopping trip are on sale.

b. Construct a data cube for best-deal products where best-deal products are those products for which the price is the lowest for this product in the given month.