mock exam

#mock exam                                                                                
SELECT users.dateType,users.name, users.eventType,like.eventType                        
FROM users
JOIN likes 
    ON users.id = likes.user_id
    AND users.dateTime = likes.dateTime  
    
    
  #revise to include only the date and transaction   
SELECT users.dateType,users.name                       
FROM users
JOIN likes 
ON users.id = likes.user_id
AND users.dateTime = likes.dateTime  
    
    
    
  #2 Using the tables above, write a SQL query to find the top 5 selling products (in terms of total units sold) by region in Q4 of 2017. 
  #Include both the distributor id as well as the name of the product in your results.  
  
  SELECT *
   FROM(  SELECT product_name, order.product id,sum(orders.no_units*orders.price) as 
   row_number() over (partition by region order by count (*) DESC)   AS region_rank
  from product
  GROUP BY product,region,) rank
  where region_rank <= 2; 
  AND order.date between '10-01-2017' and  12-31-2017'