Return the number of kids for the room reserved and checked in by DAMIEN TRACHSEL on  Sep 21, 2010.
SELECT Kids FROM Reservations WHERE CheckIn  =  "2010-09-21" AND FirstName  =  "DAMIEN" AND LastName  =  "TRACHSEL";
number of kids for the room reserved and checked in refers to Kids; checked in by a specific person on a specific date involves filtering by CheckIn date and the person's FirstName and LastName;