<p>User has a book のとき</p>
<p>多分こんな感じ</p>
<div class="code-block-container"><pre class="language-rb"><code class="language-rb">User<span class="token punctuation">.</span>joins<span class="token punctuation">(</span><span class="token symbol">:book</span><span class="token punctuation">)</span>
</code></pre></div><p>inner join すると、関連を持たない親は消えるはず</p>
<p></p>
<h1 id="%E3%83%81%E3%83%A3%E3%83%83%E3%83%88%E3%83%A1%E3%83%B3%E3%83%90%E3%83%BC%E5%8B%9F%E9%9B%86">
<a class="header-anchor-link" href="#%E3%83%81%E3%83%A3%E3%83%83%E3%83%88%E3%83%A1%E3%83%B3%E3%83%90%E3%83%BC%E5%8B%9F%E9%9B%86" aria-hidden="true"></a> チャットメンバー募集</h1>
<p>何か質問、悩み事、相談などあればLINEオープンチャットもご利用ください。</p>
<p><span class="embed-block zenn-embedded zenn-embedded-card"><iframe id="zenn-embedded__f0220edfda175" src="https://embed.zenn.studio/card#zenn-embedded__f0220edfda175" data-content="https%3A%2F%2Fline.me%2Fti%2Fg2%2FeEPltQ6Tzh3pYAZV8JXKZqc7PJ6L0rpm573dcQ" frameborder="0" scrolling="no" loading="lazy"></iframe></span><a href="https://line.me/ti/g2/eEPltQ6Tzh3pYAZV8JXKZqc7PJ6L0rpm573dcQ" style="display:none" target="_blank" rel="nofollow noopener noreferrer">https://line.me/ti/g2/eEPltQ6Tzh3pYAZV8JXKZqc7PJ6L0rpm573dcQ</a></p>
<h1 id="twitter">
<a class="header-anchor-link" href="#twitter" aria-hidden="true"></a> Twitter</h1>
<p><span class="embed-block zenn-embedded zenn-embedded-card"><iframe id="zenn-embedded__01a1d85a976be" src="https://embed.zenn.studio/card#zenn-embedded__01a1d85a976be" data-content="https%3A%2F%2Ftwitter.com%2FYumaInaura" frameborder="0" scrolling="no" loading="lazy"></iframe></span><a href="https://twitter.com/YumaInaura" style="display:none" target="_blank" rel="nofollow noopener noreferrer">https://twitter.com/YumaInaura</a></p>
<p></p>
<h1 id="%E5%85%AC%E9%96%8B%E6%97%A5%E6%99%82">
<a class="header-anchor-link" href="#%E5%85%AC%E9%96%8B%E6%97%A5%E6%99%82" aria-hidden="true"></a> 公開日時</h1>
<p>2019-06-30</p>


Rails の ActiveRecord で has_one の association を持つレコードを検索する例

チャットメンバー募集

Twitter

公開日時

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