Question

I have a MySQL DB with 2 tables.
First table:

Posts                                    
ID                      
post_title                      
post_content 
... etc

And second table with additional data:

Postmeta
ID
Post_ID (FK)
meta_key
meta_value

The data that I need is in the meta_key/value pairs. But this DB organized in the way that each row in the second table only have one piece of information.

For example (second table):

ID      Post_ID   meta_key        meta_value
1          5      info                 30

ID      Post_ID   meta_key        meta_value
2          5      additional_info      40

ID      Post_ID   meta_key        meta_value
3          6      info                 50

ID      Post_ID   meta_key        meta_value
4          6      additional_info      60

So if I run query

SELECT 
posts.id, 
posts.post_date, 
posts.post_author, 
posts.post_content, 
posts.post_title, 
postmeta.meta_id, 
postmeta.meta_key, 
postmeta.meta_value

FROM posts INNER JOIN postmeta ON posts.id = postmeta.post_id

WHERE posts.post_type = 'post'

I get back all data that I need but data from first table (ID/post_content etc) repeated many times.
But I only need data from first table once but all additional data from second table related to ID from the first table.

How I should filter all this stuff? May be some php loop?

Answer 1

You can use a mysql group_concat function like this:

select
    posts.id, 
    posts.post_date, 
    posts.post_author, 
    posts.post_content, 
    posts.post_title, 
    group_concat(postmeta.meta_id) as metaID, 
    group_concat(postmeta.meta_key) as metaKey, 
    group_concat(postmeta.meta_value_ as metaValue
from
    posts 
        INNER JOIN postmeta 
            ON posts.id = postmeta.post_id
where
    posts.post_type = 'post'
group by
    posts.id, 
    posts.post_date, 
    posts.post_author, 
    posts.post_content, 
    posts.post_title

The to split out the results in PHP you can easily use an explode function to form an array of the resulting information.