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PORails 3.2 (ActiveRecord) association order with eager loading and ordering
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copied!<p>I came upon this behavior in rails that I can't seem to find in the documentation.</p> <p>It appears that if you complicate an ActiveRecord query to the point that it lumps the underlying SQL into a "complicated" query (see below) it doesn't honor ordering specified on the associations.</p> <p>Here's my example model:</p> <pre><code>class Article < ActiveRecord::Base belongs_to :user has_many :categories, :order => :name attr_accessible :title, :user_id, :user end </code></pre> <p>If I perform a "simple" query, I can get the associated categories ordered by their name:</p> <pre><code>> Article.includes(:categories).first.categories.map &:name Article Load (0.1ms) SELECT "articles".* FROM "articles" LIMIT 1 Category Load (0.2ms) SELECT "categories".* FROM "categories" WHERE "categories"."article_id" IN (11) ORDER BY name => ["category 3059", "category 3212", "category 3240", "category 3651", "category 4371", "category 5243", "category 6176", "category 6235", "category 6468", "category 654", "category 6804", "category 6892", "category 7026", "category 8929", "category 9653"] </code></pre> <p>You can see that the categories' names are in the expected order (note: I expect the 3 digit numbered categories to be in alphabetical order due to how the database orders strings).</p> <p>This next example is a more complicated query using another associations attribute for ordering:</p> <pre><code>> Article.includes(:user, :categories).order('users.name').first.categories.map &:name Article Load (0.3ms) SELECT DISTINCT "articles".id FROM "articles" LEFT OUTER JOIN "users" ON "users"."id" = "articles"."user_id" LEFT OUTER JOIN "categories" ON "categories"."article_id" = "articles"."id" ORDER BY users.name LIMIT 1 SQL (0.2ms) SELECT "articles"."id" AS t0_r0, "articles"."title" AS t0_r1, "articles"."user_id" AS t0_r2, "articles"."created_at" AS t0_r3, "articles"."updated_at" AS t0_r4, "users"."id" AS t1_r0, "users"."name" AS t1_r1, "users"."created_at" AS t1_r2, "users"."updated_at" AS t1_r3, "categories"."id" AS t2_r0, "categories"."name" AS t2_r1, "categories"."article_id" AS t2_r2, "categories"."created_at" AS t2_r3, "categories"."updated_at" AS t2_r4 FROM "articles" LEFT OUTER JOIN "users" ON "users"."id" = "articles"."user_id" LEFT OUTER JOIN "categories" ON "categories"."article_id" = "articles"."id" WHERE "articles"."id" IN (16) ORDER BY users.name => ["category 5023", "category 728", "category 3306", "category 8170", "category 5957", "category 7190", "category 4427", "category 3435", "category 1274", "category 7251", "category 7368", "category 682", "category 2918"] </code></pre> <p>As you can see, when AR lumps the query into one of its "complicated" SQL queries order is lost to the <code>categories</code> association.</p> <p>Is this behavior expected? Is it documented somewhere that I haven't been able to find?</p> <p>Thanks!</p>

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