加入2个mysql表并按1个表中相同行的数量排序

Question

I need some help with a mysql query.

I have 2 tables,

Table 1 - Photos (photo_id, photo_url)

1----- www.someurl.com
2----- www.someurl.com
3----- www.someurl.com
4----- www.someurl.com

Table 2 - Favorites (favorite_id, user_id,photo_id)

1-------5------1
2-------5------2
3-------6------1
4-------6------3
5-------7------2
6-------7------3
7-------8------3
7-------8------4

I want to get results from photos table ordering by the favorite numbers of users.

Correct ordering must be:

1) Photo-3 (3 votes)
2) Photo-2 (2 votes)
2) Photo-1 (2 votes)
2) Photo-4 (1 vote)

Answer 1

SELECT  a.photo_url, COUNT(b.photo_ID) totalVotes
FROM    table1 a
        LEFT JOIN table2 b
            ON a.photo_ID = b.photo_id
GROUP BY a.photo_url
ORDER BY totalVotes DESC

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