mysql按類別查詢訂單頂部銷售

Question

在如何執行此查詢時遇到問題。有三個類別，ship,car,plane。我想按大多數銷售來訂購類別。

這裏是SQL小提琴http://sqlfiddle.com/#!2/e3344/1

下面是表值

id | name  | sales | category | 
    1 | mike  | 2 | ship | 
    2 | john  | 11 | car | 
    3 | david  | 13 | ship | 
    4 | pablo  | 24 | car | 
    5 | greg  | 13 | car | 
    6 | nick  | 1 | ship | 
    7 | anderson | 19 | ship | 
    8 | matt  | 10 | plane | 
    9 | robbie  | 3 | ship | 
    10 | victor  | 1 | ship | 
    11 | ben   | 11 | plane | 
    12 | rick  | 6 | ship | 
    13 | christopher | 16 | car | 
    14 | steve  | 8 | ship | 
    15 | claudio  | 9 | plane | 

如何添加了按類別和順序降序總銷售額？

Answer 1

試試group by和order by聲明。

SELECT category, sum(sales) 
FROM table 
GROUP BY category 
ORDER BY sum(sales) DESC 

編輯 就像一個建議。您的「類別」應該是數據庫模型中的額外實體。