Task: Text to Code
Input (English): Step 1: For each row in country table, find the corresponding rows in roller_coaster table.
Step 2: find each value of Country_ID in the results of step 1 along with the average Speed of the corresponding rows to each value
Output (English): SELECT T2.Name , Avg ( T1.Speed ) FROM roller_coaster AS T1 JOIN country AS T2 ON T1.Country_ID = T2.Country_ID GROUP BY T1.Country_ID