Dubai being Dubai, it has found a way around this. After all, tourism needs to bring in the money when all that oil runs out. All bars are in hotels, it's even been known for a hotel to be built just so a bar can be opened beneath it. These are generally open throughout the day, and most of the night. Avoid Ramadan as more or less everything closes during the day.
My partner and I fly to and fro from Oz to Uk every year and always stop over at Emirates Millennium Airport Hotel ( Commercial Wing - don't fall for the Tourist Wing! eeek!) Biggles Bar in the hotel tries to be an English Pub - great beer, food and service. Lots of atmosphere - we are 50+ but all age groups enjoy. Only problem ....they try to re-fill your glass before you have even thought about lining it up again! Enjoy! If you go - say hello to John, the barman from us!