php - Table referencing itself , MySQL, primary key and foreign key in same table , select statement -

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कैसे मैं श्रेणियों के कॉलम का चयन करता हूं जो दो प्रकार SubCat & amp; mainCat से संदर्भित रूप से तालिका संदर्भ में cat :

कहलाता है ( maincat_id ) संदर्भ ( cat_id < / Code>) जो प्राइमरीकी है

तालिका में डेटाबेस: 

 cat_id catname maincat_id cat_type 1 हैलो नल 1 2 एक 3 2 3 परीक्षा 1 2 4 ते 3 3 2
< P> जैसा कि आप देख रहे हैं कि अगर cat_type = 1 है तो यह उपकैट है।

मुझे सिर्फ तालिका की आवश्यकता है सबकैट मुख्य कैट जो इसे संबंधित है: 

 catname Root_name एक टेस्ट टेस्ट हैलो है ते 3 परीक्षा  
 अधिक जानकारी: हमारे पास श्रेणियों की एक मेज है जिसे 'बिल्ली कहते हैं ', इसमें (मुख्य श्रेणियाँ) और (उप श्रेणियां) हैं, जो छोटे पेड़ (सिर्फ एक स्तर की गहराई) बनाती हैं।   
 
 
 आप बस उपयोग कर सकते हैं इसके लिए एक सरल आंतरिक सम्मिलन:  
  SELECT t1.catname AS श्रेणी, t2.catname AS उपश्रेणी से cat t1 INNER जोड़ी बिल्ली t2 ON t1.cat_id = t2.maincat_id WHERE t1.cat_type = 1  
 
 आखिरकार, मुझे आशा है कि मैं आपके प्रश्न को सही समझता हूं, और यही आपकी जरूरत है। 
 
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