Complex SQL query, checking column values in multiple tables

问题

I have a pretty huge SQL query to check for notifications, and I have several different types of notifications in the table, IE: posts, likes, comments, photoComments, photoLikes, videoLikes, etc. (Always adding more to it) And I have come into a problem, I'm not really sure how to best do this anymore. Thus far the way I have done it is working perfectly, and really quite easy to add to, however this one notification Type I have to check more than just one other table, I have to check two others and I haven't been able to get it to work.

So here it is: (This is only one part of my huge query, the only relevant part really)

n.uniqueID = ANY (
              SELECT photos.id
              FROM photos INNER JOIN posts ON (photos.id=posts.post)
              WHERE photos.state=0
              AND posts.state=0 
              AND posts.id = ANY (
                                   SELECT likes.postID FROM likes
                                   INNER JOIN posts ON (posts.id=likes.postID)
                                   WHERE likes.state=0 AND posts.state=0
                                  )
                )

So basically all I really need to do is check the state columns in each table because that says whether or not it is deleted or not (if it's not 0 then it's deleted and shouldn't be returned) So it would be like:

IF photos.state=0 AND posts.state=0 AND likes.state=0 return it.

n.uniqueID, posts.post, and photo.id will all be the same value.
posts.id and likes.postID will also be the same value.

My issue is that it doesn't seem to be checking the likes.state, I don't think.

回答1:

I think you just want to join the three tables together in a single query:

n.uniqueID = ANY (
              SELECT photos.id
              FROM photos INNER JOIN
                   posts
                   ON photos.id=posts.post inner join
                   likes
                   on posts.id = likes.postId
              WHERE photos.state=0 and
                    posts.state=0 and
                    likes.state = 0
                  )

Your logic is not to return when there is a like or post with the state of 0. It seems to be that all the likes and posts have a state of zero. For this, do an aggregation with a having clause:

n.uniqueID = ANY (
              SELECT photos.id
              FROM photos INNER JOIN
                   posts
                   ON photos.id=posts.post inner join
                   likes
                   on posts.id = likes.postId
              where photos.state = 0
              group by photos.id
              having MAX(posts.state) = 0 and MAX(likes.state) = 0

来源：https://stackoverflow.com/questions/14222605/complex-sql-query-checking-column-values-in-multiple-tables

标签

mysql

sql

join

inner-join