Question

Joining 4 tables in MySQL to retrive data.

I need the best way to join 4 tabels:

1. Users

ID        NAME
1          me
2          you 
3          her

2. Articles

ID   USER_ID   ARTICLE
1       1         etc
2       1         etc
3       2         third  

3. Article_comments

ID    ARTICLE_ID    COMMENT    
1        1            etc
2        1            etc
3        3            etc 

4. Article points

ID ARTICLE_ID   POINTS
1      1         100  
2      1         200
3      2          50 
4      2          10   

I need a way to join them to retrieve:

ARTICLE | USERNAME | TOTAL COMMENTS PER ARTICLE | TOTAL POINTS PER ARTICLE  

For example: For article 1: etc | me | 2 | 350
for 2 : etc | you | 0 | 60 and so one for all of them.

Answer 1

SELECT
    Articles.ID,
    Articles.USER_ID,
    Articles.ARTICLE,
    Users.NAME,
    COUNT(Article_comments.ID) AS `num_comments`,
    SUM(Article_points.POINTS) AS `points`
FROM
    Articles
INNER JOIN
    Users
ON
    Articles.USER_ID = Users.ID
LEFT OUTER JOIN
    Article_comments
ON
    Article_comments.ARTICLE_ID = Articles.ID
LEFT OUTER JOIN
    Article_points
ON
    Article_points.ARTICLE_ID = Articles.ID
GROUP BY
    Articles.ID