Database: yelp
Question: How many businesses in " San Diego " has Christine reviewed in 2010 ?
SQL:
SELECT COUNT ( DISTINCT t1.name ) FROM review AS t2 JOIN business AS t1 ON t2.business_id  =  t1.business_id JOIN USER AS t3 ON t3.user_id  =  t2.user_id WHERE t1.city  =  "San Diego" AND t2.year  =  2010 AND t3.name  =  "Christine";