How many kids stay in the room DAMIEN TRACHSEL checked in on Sep 21, 2010?
SELECT Kids FROM Reservations WHERE CheckIn  =  "2010-09-21" AND FirstName  =  "DAMIEN" AND LastName  =  "TRACHSEL";
number of kids = Kids; stay in the room refers to a record in Reservations; checked in on a specific date refers to CheckIn = '2010-09-21'; checked in by a person refers to FirstName = 'DAMIEN' AND LastName = 'TRACHSEL';