Database: yelp
Question: find the sum of checkins in Moroccan restaurant in " Los Angeles " on Friday
SQL: select sum ( t4.count ) from category as t2 join business as t1 on t2.business_id  =  t1.business_id join category as t3 on t3.business_id  =  t1.business_id join checkin as t4 on t4.business_id  =  t1.business_id where t1.city  =  "los angeles" and t2.category_name  =  "moroccan" and t3.category_name  =  "restaurant" and t4.day  =  "friday"