MySQL从两个表计数

Question

I have two tables: loan and librarian.

librarian: idLibrarian, libName and libPassword loan: idLoan,...,idLibrarian

Each loan has a idLibrarian. What I'm trying to do is find which librarian has the most loans. I can count number of librarians and number of loans. But i can't figure out how to group all the loans by idLibrarian and find the one with the highest amount of loans.

Answer 1

select idLibrarian, count(*) from loan group by idLibrarian order by 2 desc

第一行将是借贷最多的图书馆员，等等。