MySQL查詢組數據轉換成不同的範圍

我發現這個在這裏解決， sql query that groups different items into buckets MySQL查詢組數據轉換成不同的範圍

它運作良好，只要有對所有範圍的數據。如果沒有數據，我希望查詢返回0。

所以，如果我的表是：

item_name | price 
i1  | 2 
i2  | 22 
i3  | 4 
i4  | 26 
i5  | 44 
i6  | 6

我想輸出：

下面的查詢將不會顯示效果爲0計數的情況。

select 
     case when price >= 0 and price <= 10 then " 0 - 10" 
      when price > 10 and price <= 20 then " 10 - 20" 
      when price > 20 and price <= 30 then " 20 - 30" 
      when price > 30 and price <= 40 then " 30 - 40" 
      when price > 40 and price <= 50 then " 40 - 50" 
      else "over 50" 
     end PriceRange, 
     count(*) as TotalWithinRange 
    from 
     YourTable 
    group by 1

有沒有人有這方面的解決方案？

來源

2015-05-19 user3803131

你有一個顯示問題。基本查詢很簡單：'選擇cast（價格/ 10作爲int），通過cast（price/10 as int）'從yourtable組計數（*），然後使用一些客戶端代碼將轉換值格式化爲您的範圍。 –

您需要構建包含所有價格範圍的內聯表。然後根據您的查詢，以獲得期望的結果派生表執行LEFT JOIN：

SELECT x.PriceRange, COALESCE(TotalWithinRange, 0) AS TotalWithinRange 
FROM (
    SELECT "0 - 10" AS PriceRange 
    UNION SELECT "10 - 20" 
    UNION SELECT "20 - 30" 
    UNION SELECT "30 - 40" 
    UNION SELECT "40 - 50" 
    UNION SELECT "over 50") x 
LEFT JOIN ( 
    SELECT 
     CASE when price >= 0 and price <= 10 then "0 - 10" 
      when price > 10 and price <= 20 then "10 - 20" 
      when price > 20 and price <= 30 then "20 - 30" 
      when price > 30 and price <= 40 then "30 - 40" 
      when price > 40 and price <= 50 then "40 - 50" 
      else "over 50" 
     END AS PriceRange, 
     COUNT(*) as TotalWithinRange 
    FROM YourTable 
    GROUP BY 1) y ON x.PriceRange = y.PriceRange

SQL Fiddle Demo

來源

2015-05-19 20:31:53

集團通過TotalWithinRange，所以它會統計每個類別

來源

2015-05-19 20:12:38

我無法對TotalWithinRange進行分組，導致出現SQL錯誤 – user3803131

這可能不是最有效的答案，但你可以嘗試爲每個組單獨SUM(CASE)語句。例如：

SUM(CASE WHEN price >= 0 AND price <= 10 THEN 1 ELSE 0 END) AS "0-10"

依此類推。這應該打印SUMs爲0的類別。

來源

2015-05-19 20:31:42 RedClouds

MySQL查詢組數據轉換成不同的範圍

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