MySQL返回相同数据的不同行

Question

I am trying to get data from reviews table then, join the same table again but find different data (likes) based on the id of the first table (reviews) and find the corresponding description from yet another joined table (descriptions).

I know this might be hard to visualize but maybe someone will know why the likes from the second reviews table return the same data for different rows:

SELECT r.title, co.likes, d.description
FROM reviews r
INNER JOIN reviews co
INNER JOIN reviews_descriptions d
ON co.id = d.review_id
WHERE co.parent = 52
AND r.id = 52;

The result is two rows in which title and likes have the same data while the description field grabs different data (the correct way). Likes should have different data for each row.

Help please.

Answer 1

An alternative for writing this and I believe this is what you are looking for:

SELECT r.title, co.likes, d.description
FROM reviews r, reviews co, review_descriptions d
WHERE co.parent = r.id AND d.review_id = co.id AND r.id = 52;

Since you are matching co.parent to 52 and r.id to 52, then you should have a join on co.parent = r.id, however, you should rarely have to do a join on the same table. I think your tables are poorly formatted or you don't need to do the join in the first place and should be able to use r.likes instead of co.likes.