復合MySQL中每組需要的最大n個加入sql

Question

我將3個表與此查詢

SELECT DISTINCT a.number, c.quantity, c.retail_price 
FROM catalog.product `a`
JOIN catalog.product_variation `b` ON a.id = b.product_id
JOIN catalog.price_regular `c` ON b.id = c.product_variation_id
WHERE c.retail_price BETWEEN 5 AND 6 AND a.status_id = 1
ORDER BY a.number, c.retail_price DESC

我得到這個結果集

number|quantity|retail_price
---------------------
1007  | 288    | 5.750
1007  | 48     | 5.510
1007  | 576    | 5.460
1007  | 96     | 5.240
1007  | 576    | 5.230
1007  | 144    | 5.120
1006  | 200    | 5.760
1006  | 100    | 5.550
1006  | 200    | 5.040
1006  | 500    | 5.010

我需要的是結果僅在quantity列中包含最大價值的行，並且還包含具有retail_price最大的行。 所以我需要的結果集看起來像這樣

number|quantity|retail_price
---------------------
1006  | 500    | 5.010
1007  | 576    | 5.460

我在SO上找到了幾篇文章，但在加入多個表時卻沒有幫助。 我需要一條sql語句來獲取上面指定的結果集

Answer 1

這是一個簡單的GROUP BY查詢

SELECT a.number, max(c.quantity) as qty, max(c.retail_price) as price 
FROM catalog.product `a` 
JOIN catalog.product_variation `b` ON a.id = b.product_id 
JOIN catalog.price_regular `c` ON b.id = c.product_variation_id 
WHERE c.retail_price BETWEEN 5 AND 6 
AND a.status_id = 1 
GROUP BY a.number;