On the site @
http://www.alhambratickets.com , click on your language version first, then click the TICKETS tab, then at left click the link for TYPES OF TICKETS. There, you'll see the different... ummm.. types of tickets!
I'll copy and paste the info for you here:
Types of Tickets
1. General day-time visits: This includes the visitable areas in the Alcazaba, the Nasrid Palaces and the Generalife.
You will be admitted to these visitable areas within the time established for the type of ticket you have acquired (morning, afternoon or night), once inside any one of these areas you may stay until it closes.
(Monday to Sunday) November to February March to October
Morning ticket 8:30 to 14:00 8:30 to 14:00
Afternoon ticket 14:00 to 18:00 14:00 to 20:00
2. Visit to the gardens: During the day visit it also possible to acquire a type of ticket which allows you to visit the main garden areas of the Monument.
(Monday to Sunday) November to February March to October
Morning ticket 8.30 to 14.00 8.30 to 14.00
Afternoon ticket 14.00 to 18.00 14.00 to 20.00
This ticket does not include the visit to the Nasrid Palaces or the Patio de la Acequia.
This ticket may only be reserved in branches of the Bilbao Vizcaya Argentaria Bank or through telephone bank
3. Night Visit: This only includes the visitable areas of the Nasrid Palaces.
Admittance to the Nasrid palaces is limited to the times indicated on the ticket, once inside you may stay there until closing time.
November to February March to October
Friday and Saturday: 20:00 to 21:30
Every day except Sundays and Mondays. 22:00 to 23:30
This ticket does not carry the right to visit the Monument during the day-time.
NOTE: This information is supplied by the Patronato of the Alhambra and the Generalife.