1 . select * from Reader where Department = ' Law Department '

2. Select the library card number, book number and borrowing date in the book borrowing registration with an empty book return period.

3. Select t 1. Book number, t 1. Return date -t2. The borrowing date comes from the borrowing registration t 1, and the borrowing registration t2 is t 1. Serial number =t2. Serial number and t 1. Library card number =t2. Library card number and t.

4. Select ISBN, count(*)by ISBN from the book borrowing registration group.

5. Select a publishing house, select the amount (price) from the book group according to the publishing house, and sort by the amount (price) desc.