Question

I am trying to make simple mysql select query, I have 3 tables

post: post_id...
tags: tag_id, tag_name
post_tag: id_post, id_tag

and I wrote this query:

$sql=mysql_query("select * from post 
LEFT JOIN post_tag 
ON post_tag.id_post = post.post_id
LEFT JOIN tags
ON post_tag.id_tag = tags.tag_id    
GROUP BY post_id
ORDER BY post_id 
DESC LIMIT 5");    

but I am getting only one tag per post even there is more tags with same post_id?

while($row=mysql_fetch_array($sql)) 
{
  $post_id =$row['post_id '];           
  $tag_name=$row['tag_name'];

  echo $post_id $tag_name;
}   

Answer 1

You could use something like:

SELECT post_id, GROUP_CONCAT(tag_name) AS tag_name FROM post 
LEFT JOIN post_tag 
ON post_tag.id_post = post.post_id
LEFT JOIN tags
ON post_tag.id_tag = tags.tag_id    
GROUP BY post_id
ORDER BY post_id 
DESC LIMIT 5

This will give you one record for each post with a comma seperated list of every tagname that is linked to that post.