title: Database Normalization on LEFT JOIN?
body: <p>I wanted to load all my post tags with a single query into the MySQL server.<br><br>Now, I have decided to use LEFT JOIN because if there is no tags are associated with my post then also I will have that post, or you have any other suggestion for this?<br>Here is my query:</p>
  
  <pre><code>SELECT * FROM tags, tags_map 
  LEFT JOIN posts on posts.cid = tags_map.pid 
  WHERE tags.tag_id = tags_map.tid
  </code></pre>
  
  <p>Now the problem is duplicate data, for example if a post has three tags then the post itself will repeat three time! <br>In this case should I run another query for each post to have their tags? or can i get them all with a single query but without duplicate data?</p>