If the restaurant is a buffet, an all you can eat family style (like Ohana or Garden Grill or LTT), or a fixed price, fixed menu (like Akershus or CRT) then everyone at the table age 3 or over will be charged for the full meal whether they eat or not.
If it isn't, it's up to the restaurant. Most reports from most restaurants are that you can probably share with your child but you would probably need to order her a drink if she wants one.