How many restaurant is the Sandwich type restaurant?
SELECT count(*) FROM Restaurant JOIN Type_Of_Restaurant ON Restaurant.ResID =  Type_Of_Restaurant.ResID JOIN Restaurant_Type ON Type_Of_Restaurant.ResTypeID = Restaurant_Type.ResTypeID GROUP BY Type_Of_Restaurant.ResTypeID HAVING Restaurant_Type.ResTypeName = 'Sandwich'
count of restaurants of a specific type (Sandwich) refers to counting the number of entries in a table where the restaurant type matches 'Sandwich'; joining tables to match restaurant IDs with their types;