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POMySql scoping problem with correlated subqueries
 

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    <p>I'm having this Mysql query, It works:</p> <pre><code>SELECT nom ,prenom ,(SELECT GROUP_CONCAT(category_en) FROM (SELECT DISTINCT category_en FROM categories c WHERE id IN (SELECT DISTINCT category_id FROM m3allems_to_categories m2c WHERE m3allem_id = 37) ) cS ) categories ,(SELECT GROUP_CONCAT(area_en) FROM (SELECT DISTINCT area_en FROM areas c WHERE id IN (SELECT DISTINCT area_id FROM m3allems_to_areas m2a WHERE m3allem_id = 37) ) aSq ) areas FROM m3allems m WHERE m.id = 37 </code></pre> <p>The result is:</p> <pre><code>nom prenom categories areas Man Multi Carpentry,Paint,Walls Beirut,Baalbak,Saida </code></pre> <p>It works correclty, but only when i hardcode into the query the id that I want (37). I want it to work for all entries in the m3allem table, so I try this:</p> <pre><code>SELECT nom ,prenom ,(SELECT GROUP_CONCAT(category_en) FROM (SELECT DISTINCT category_en FROM categories c WHERE id IN (SELECT DISTINCT category_id FROM m3allems_to_categories m2c WHERE m3allem_id = m.id) ) cS ) categories ,(SELECT GROUP_CONCAT(area_en) FROM (SELECT DISTINCT area_en FROM areas c WHERE id IN (SELECT DISTINCT area_id FROM m3allems_to_areas m2a WHERE m3allem_id = m.id) ) aSq ) areas FROM m3allems m </code></pre> <p>And I get an error:</p> <blockquote> <p>Unknown column 'm.id' in 'where clause'</p> </blockquote> <p>Why? From the MySql manual:</p> <pre><code>13.2.8.7. Correlated Subqueries [...] Scoping rule: MySQL evaluates from inside to outside. </code></pre> <p>So... do this not work when the subquery is in a SELECT section? I did not read anything about that.</p> <p>Does anyone know? What should I do? It took me a long time to build this query... I know it's a monster query but it gets what I want in a single query, and I am so close to getting it to work!</p> <p>Can anyone help?</p>
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