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POHow can I query the same table twice with this code (keeping GROUP_CONCAT)?
 

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  1. POHow can I query the same table twice with this code (keeping GROUP_CONCAT)?
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    <p>In the code below, which is doing largely what I want, I am querying an attributes table that is linked to a 'venues' table by a venue_attribute table giving a many-to-many.</p> <p>I am doing this to improve performance when displaying a large list over individual venue pages, where I use factory to load up venue objects. So far this new call is saving me a lot of time. </p> <p>Firstly I would like to know why I had to use DISTINCT with GROUP_CONCAT to avoid multiple values being shown per venue under a.name? I don't see where it joins twice? </p> <p>My second challenge is retrieving a rating value which is held in the attributes table, separately from the GROUP_CONCAT returned value. (I have put the table structure below the query). The rating returns within the GROUP_CONCAT (a.name) value but there is only one per venue and I need to show it in a separate column, such as a.rating, within the select statement. I should perhaps hold the rating value in the venue table, and will, if it is not easily retrievable - but I'm interested to see what MYSQL can do and I'm rather basic in my skill levels. </p> <p>Thanks for your time. </p> <pre><code>SELECT v.venue_id, v.name, v.suburb, v.venue_email, v.venue_phone, GROUP_CONCAT(DISTINCT a.name) AS attributes, v.review_count, vi.image_thumb_path FROM venues AS v LEFT JOIN venue_attribute AS va ON v.venue_id = va.venue_id LEFT JOIN attribute AS a ON a.att_id = va.attribute_id LEFT JOIN venue_review AS vr ON vr.venue_id = v.venue_id LEFT JOIN venue_image AS vi ON vi.venue_id = v.venue_id WHERE v.status = 1 GROUP BY v.name; Table attribute =============== att_id, type, name, abbreviation, synonyms, description, scope --------------- att_id int(11) PK type enum('transport','purpose','parking','site_control','authorisations','permissions','facilities','rating') name varchar(255) abbreviation varchar(32) synonyms varchar(255) description mediumtext scope enum('global') </code></pre>
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    1. USSaminOz
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    2. VO
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    1. COIf there's only one attribute.rating value for a venue, but there is a one-to-many relationship between venues and attribute, which row is the rating in? All of them?
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      1. USAmi
    2. CO@Ami, I think this subset of my question answers your question? "I am querying an attributes table that is linked to a 'venues' table by a venue_attribute table giving a many-to-many"
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      1. POHow can I query the same table twice with this code (keeping GROUP_CONCAT)?
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    3. COAnd the answer is?
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      1. USAmi
 

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