SUM SQL 多表 GROUP BY

Question

Hello I can't seem to get this question answered.

the question is : 3.5 For each horse that has won a prize, list the horse name, horse_id and total prize money won.

have tried:

SELECT horse_name, horse.horse_id, SUM(prizemoney) 
FROM horse 
JOIN entry ON entry.horse_id=horse.horse_id 
JOIN prize ON entry.event_id=prize.event_code 
GROUP BY horse_name

dont get the right answer

This is my answer:

This is the teachers answer:

Answer 1

If you ignore PLACE in your joins then you will get the wrong answer. Include PLACE in the join logic!

SELECT horse_name, horse.horse_id, SUM(prizemoney) 
FROM horse 
JOIN entry ON entry.horse_id=horse.horse_id 
JOIN prize ON entry.event_id=prize.event_code 
          
GROUP BY horse_name, horse.horse_id

also: include ALL non-aggregating columns in the grouop by clause