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  1. PO
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    <p>You're probably missing an index. With the following schema, this same query hit the index for every table:</p> <pre><code>CREATE TABLE `products` ( `id` int(11) NOT NULL AUTO_INCREMENT, `deleted` tinyint(1) unsigned NOT NULL DEFAULT '0', `status` varchar(255) NOT NULL DEFAULT 'listed', `images` varchar(255) DEFAULT NULL, `created` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP, PRIMARY KEY (`id`) ) ENGINE=InnoDB DEFAULT CHARSET=utf8; CREATE TABLE `tags` ( `id` int(11) NOT NULL AUTO_INCREMENT, `tag` varchar(255) NOT NULL, PRIMARY KEY (`id`) ) ENGINE=InnoDB DEFAULT CHARSET=utf8; CREATE TABLE `products_tags` ( `product_id` int(11) NOT NULL, `tag_id` int(11) NOT NULL DEFAULT '0', PRIMARY KEY (`product_id`,`tag_id`) ) ENGINE=InnoDB DEFAULT CHARSET=utf8; </code></pre> <p>Here are the results of the EXPLAIN query:</p> <pre><code>EXPLAIN SELECT p.id AS id, GROUP_CONCAT(t.tag SEPARATOR '|') AS tags, UNIX_TIMESTAMP(p.created) AS created FROM products p INNER JOIN products_tags pt ON pt.product_id = p.id INNER JOIN tags t ON t.id = pt.tag_id WHERE p.deleted = 0 AND (p.images IS NOT NULL OR p.images &lt;&gt; '') AND p.status LIKE 'listed' GROUP BY p.id; +----+-------------+-------+--------+---------------+---------+---------+----------------+------+-------------+ | id | select_type | table | type | possible_keys | key | key_len | ref | rows | Extra | +----+-------------+-------+--------+---------------+---------+---------+----------------+------+-------------+ | 1 | SIMPLE | p | index | PRIMARY | PRIMARY | 4 | NULL | 1 | Using where | | 1 | SIMPLE | pt | ref | PRIMARY | PRIMARY | 4 | test.p.id | 1 | Using index | | 1 | SIMPLE | t | eq_ref | PRIMARY | PRIMARY | 4 | test.pt.tag_id | 1 | | +----+-------------+-------+--------+---------------+---------+---------+----------------+------+-------------+ 3 rows in set (0.00 sec) </code></pre>
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    1. POView of products with tags and GROUP_CONCAT
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    1. This table or related slice is empty.
    1. USMatthew Ratzloff
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    1. COI was missing indexes indeed! That is such a stupid mistake... But thanks Matthew! Thank you very much!
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      1. USEber Freitas Dias
    2. CONo problem, glad to help!
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