MySQL insert using double list comprehension

gistfile1.py

def reward_close(data):
	fields = ['id','name','image_url','hint','message','type','allow_duplicates','active']
	print "Processing %i rewards" % len(data)
	c.executemany( """INSERT INTO `ford_post_season`.`bv_rewards` (`%s`) VALUES (%s)""" % ('`, `'.join(fields), ', '.join(['%s'] * len(fields))), 
			[[reward[field].encode('utf-8') if hasattr(reward[field], 'encode') else reward[field] for field in fields] for reward in data])