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POProblems with query optimization
 

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  1. POProblems with query optimization
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    <p>I had two queries - one that selects <code>group_id</code> by knowing the <code>post_id</code>, and one that checks that user is in that group. I tried to optimize them - put them together, but it now throws an error...</p> <pre><code>SELECT COUNT(bio_community_group_members.id) AS count FROM `bio_community_group_members` JOIN `bio_community_posts` ON (`bio_community_posts`.`id` = `180`) WHERE `bio_community_group_members`.`group_id` = 'bio_community_posts.group_id' AND `bio_community_posts`.`user_id` = '34' </code></pre> <p>It says:</p> <blockquote> <p>Unknown column '180' in 'on clause'.</p> </blockquote> <p>Problem: I have that entry!</p> <p>Table structure:</p> <p><code>bio_community_posts</code>:</p> <ul> <li><code>id</code>,</li> <li><code>user_id</code>,</li> <li><code>group_id</code>,</li> <li>other stuff;</li> </ul> <p><code>bio_community_group_members</code>:</p> <ul> <li><code>id</code>,</li> <li><code>user_id</code>,</li> <li><code>group_id</code>,</li> <li><code>status</code>,</li> <li>other stuff;</li> </ul> <p>I need to retrieve <code>status</code> from <code>bio_community_group_members</code> if it exists. That <code>count</code> thing was just because I didn't knew how to start to build my query. :(</p> <p>Thanks in advice.</p> <p><strong>Edit:</strong></p> <p>Hmm... now it works..... but any idea how to optimize those two queries and get one that also selects <code>status</code>?</p> <pre><code>SELECT `group_id` FROM `bio_community_posts` WHERE `id` = 180 SELECT COUNT(id) AS count FROM `bio_community_group_members` WHERE `group_id` = 41 AND `user_id` = '34' </code></pre> <p><strong>Edit #2:</strong></p> <p>This is what I was looking for:</p> <pre><code>SELECT `bio_community_group_members`.`status` FROM `bio_community_group_members` JOIN `bio_community_posts` ON `bio_community_posts`.`group_id` = `bio_community_group_members`.`group_id` WHERE `bio_community_group_members`.`group_id` = 41 AND `bio_community_group_members`.`user_id` = '34' AND `bio_community_posts`.`id` = '180' GROUP BY `bio_community_group_members`.`status` </code></pre> <p>Thanks! :)</p> <p><strong>Edit #3:</strong></p> <p>I guess that i need something like this...</p> <pre><code>SELECT `bio_community_group_members`.`status` FROM `bio_community_group_members` JOIN `bio_community_posts` ON `bio_community_posts`.`group_id` = `bio_community_group_members.group_id` WHERE `bio_community_posts`.`id` = '180' AND `bio_community_posts`.`user_id` = '34' </code></pre> <p>But:</p> <blockquote> <p>[Err] 1054 - Unknown column 'bio_community_group_members.group_id' in 'on clause'.</p> </blockquote> <p><strong>Edit #4:</strong></p> <p>Just found a bug in the query. Here is the ultimate solution:</p> <pre><code>SELECT `bio_community_group_members`.`status` FROM `bio_community_group_members` JOIN `bio_community_posts` ON `bio_community_posts`.`group_id` = `bio_community_group_members`.`group_id` WHERE `bio_community_posts`.`id` = '180' AND `bio_community_posts`.`user_id` = '34' </code></pre>
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    1. USdaGrevis
    1. USdaGrevis
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    1. CORemove back ticks. Example: id = 180.
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      1. USJK.
    2. COSee my updated answer.
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      1. POProblems with query optimization
      1. USAndreas Ågren
 

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