sql - Adding averages to a table -

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मेरे पास एक टेबल है 

  | स्थान | यूनिट | ... + ---------- | ------ + ---- | ए | 1 | ... | ए | 1 | ... | बी | 1 | ... | ए | 2 | ... | सी | 2 | ... | ... | ... | ...

और मैं प्रत्येक इकाई के लिए 'औसत' स्थान मान के साथ एक नई तालिका की गणना करना चाहता हूं, निम्न अर्थ में: 

  | स्थान | यूनिट | वजन | + ---------- | ------ + -------- + | ए | 1 | 0.6667 | | बी | 1 | 0.3333 | | ए | 2 | 0.5 | | सी | 2 | 0.5 | | ... | ... | ... |

निश्चित रूप से कुल योग प्राप्त करने के लिए पर्याप्त है 

  इकाई, स्थान, गणना (*) तालिका 1 समूह से यूनिट, स्थान से चुनें;

और तालिका बनाने के लिए 

  तालिका तालिका 2 (यूनिट नवरेचार (50), स्थान इंट, वज़न फ्लोट);

लेकिन मुझे यकीन नहीं है कि इसे औसत डेटा के साथ कैसे आबाद करना है। (यह मुश्किल नहीं है, लेकिन किसी भी तरह मैं फँस गया हूँ ... यह कई सालों से जब मैंने SQL सर्वर पर काम किया है।)

आप इसके लिए COUNT ओवर का उपयोग कर सकते हैं: 

  अलग स्थान, इकाई, कास्ट (गणना (*) से अधिक (इकाई द्वारा विभाजन) चुनें , स्थान) दशमलव के रूप में) / कास्ट (गणना (*) ओवर (दशमलव के रूप में इकाई द्वारा)) यूनिट, स्थान द्वारा मीबेल ऑर्डर से वजन के रूप में;


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