sql - Activerecord how to get all unique belongs_to attributes in a set? -

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मेरे पास एक मॉडेल पोस्ट और मॉडेल श्रेणियाँ के साथ एक रेल आवेदन है।

श्रेणी belongs_to पोस्ट

मैं प्रति पृष्ठ 20 पदों को प्रदर्शित करने के लिए पृष्ठ पर अंक लगाना का उपयोग कर रहा हूं, और प्रत्येक पृष्ठ पर मुझे श्रेणियों द्वारा फ़िल्टर करने के लिए एक फिल्टर है।

अब तक, मैं इस पर आधारित श्रेणियों की सूची मुद्रित करता हूं पदों का पूरा सेट, उप-समुच्चय नहीं, जो कि पृष्ठांकित पेज का गठन करता है।

इसलिए जब मैंने अपनी क्रिया में पहले किया था: 

  home do @posts = Posts.paginate (पृष्ठ: पैराम्स [: पृष्ठ], प्रति पृष्ठ: 20) @ श्रेणी = श्रेणी.ऑल respond_to do format | Format.html एंड एंड

मैं श्रेणियों को कैसे वर्गीकृत कर सकता हूं जैसे कि इसमें श्रेणियों के संपूर्ण डाटाबेस की बजाय @ पोस्ट से सभी अनूठी श्रेणियों की सूची है।

कृपया वर्ग के रूप में प्रयास करें। Joins (: posts) .paginate (पेज: params [: page], per_page : 20) .युनीक ।


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