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我写了下面的代码来计算平均得分为商业,现在我想在业务类别的TOP 2的业务,我尝试添加HAVING COUNT(*) <= 2
,但它不工作...如何获得oracle sql中每个类别的前N个业务?
SELECT r.Bussiness_ID, b.Bussiness_Name, c.Catg_name, AVG(r.Rating)
FROM review r,bussiness b, busn_catg c
WHERE b.Bussiness_ID = r.Bussiness_ID
AND b.Category = c.Catg_ID
GROUP BY r.Bussiness_ID,b.Bussiness_Name, c.Catg_name
ORDER BY c.Catg_name, AVG(r.Rating);