Christine ได้ตรวจสอบธุรกิจจำนวนเท่าใดใน 'San Diego' ในปี 2010 ?ไม่จำเป็นต้องใช้ตารางทั้งหมด
How many businesses in ' San Diego ' has Christine reviewed in 2010 ?It is not neccessary to use all the tables.
 business:  bid [ int]  business_id [ varchar]  name [ varchar]  full_address [ varchar]  city [ varchar]  latitude [ varchar]  longitude [ varchar]  review_count [ bigint]  is_open [ tinyint]  rating [ float]  state [ varchar] 
SELECT COUNT(DISTINCT (business.name)) FROM business, review, user WHERE business.city = 'San Diego' AND review.business_id = business.business_id AND review.year = 2010 AND user.name = 'Christine' AND user.user_id = review.user_id