MySQL应该使用哪个查询语句？

问题描述

我有一个如下所示的数据集，例如，第1行，对于价格为3美元的商品，进行了0次购买，对于价格为30美元的商品，进行了3​​次购买。我将需要编写一个查询，以通过将价格归类为“ 0-10”，“ 11-20”，“ 21-30”，“ 31-40”的价格范围来提供购买的通行证的摘要。我认为应该在何时使用，但不确定如何使用。请帮忙。

+-----------------+-----------------+--------------------------+--------------------------+
| price_category1 | price_category2 | purchase_count_category1 | purchase_count_category2 |
+-----------------+-----------------+--------------------------+--------------------------+
|               3 |              30 |                        0 |                        3 |
|              20 |               6 |                        1 |                        4 |
|              25 |              11 |                        4 |                        0 |
|              17 |              12 |                        0 |                        1 |
+-----------------+-----------------+--------------------------+--------------------------+

+------+-------+-------+-------+
| 0-10 | 11-20 | 21-30 | 31-40 |
+------+-------+-------+-------+
|    4 |     2 |     7 |     0 |
+------+-------+-------+-------+

解决方法

您可以在下面尝试。

Working Solution

WITH MAIN
     AS (SELECT 3 AS price_category1,30 AS price_category2,0 purchase_count_category1,3 AS purchase_count_category2
           FROM DUAL
         UNION ALL
         SELECT 20 AS price_category1,6 AS price_category2,1 purchase_count_category1,4 AS purchase_count_category2
           FROM DUAL
         UNION ALL
         SELECT 25 AS price_category1,11 AS price_category2,4 purchase_count_category1,0 AS purchase_count_category2
           FROM DUAL
         UNION ALL
         SELECT 17 AS price_category1,12 AS price_category2,1 AS purchase_count_category2
           FROM DUAL),M2
     AS (SELECT price_category1 CAT,purchase_count_category1 CNT FROM MAIN
         UNION
         SELECT price_category2,purchase_count_category2 FROM MAIN)
  SELECT CASE
            WHEN CAT >= 0 AND CAT < 11 THEN '0-10'
            WHEN CAT >= 11 AND CAT < 21 THEN '11-20'
            WHEN CAT >= 21 AND CAT < 31 THEN '21-30'
         END
            CAT,SUM (CNT) SUMM
    FROM M2
GROUP BY CASE
            WHEN CAT >= 0 AND CAT < 11 THEN '0-10'
            WHEN CAT >= 11 AND CAT < 21 THEN '11-20'
            WHEN CAT >= 21 AND CAT < 31 THEN '21-30'
         END

,

SELECT SUM(CASE WHEN price_category1 BETWEEN 0 AND 10 
                THEN purchase_count_category1 
                END) + SUM(CASE WHEN price_category2 BETWEEN 0 AND 10  
                                THEN purchase_count_category2 
                                END) AS `0-10`,SUM(CASE WHEN price_category1 BETWEEN 11 AND 20
                THEN purchase_count_category1 
                END) + SUM(CASE WHEN price_category2 BETWEEN 11 AND 20
                                THEN purchase_count_category2 
                                END) AS `11-20`,SUM(CASE WHEN price_category1 BETWEEN 21 AND 30 
                THEN purchase_count_category1 
                END) + SUM(CASE WHEN price_category2 BETWEEN 21 AND 30
                                THEN purchase_count_category2 
                                END) AS `21-30`
FROM source_table

或

SELECT SUM(CASE WHEN cat BETWEEN 0 AND 10 
                THEN cnt
                END )  AS `0-10`,SUM(CASE WHEN cat BETWEEN 11 AND 20
                THEN cnt
                END )  AS `11-20`,SUM(CASE WHEN cat BETWEEN 21 AND 30 
                THEN cnt
                END )  AS `21-30`
FROM ( SELECT price_category1 cat,purchase_count_category1 cnt
       FROM source_table
       UNION ALL
       SELECT price_category2,purchase_count_category2
       FROM source_table ) src

PS。此解决方案提供“水平”输出-包含所有所需统计信息的一行。如果需要“垂直”输出，请使用solution提供的ismetguzelgun。

请注意-我的解决方案是不可扩展的（如果您需要更改范围数量或边界，则必须更改查询文本），而将硬编码范围边界转换为根据CTE或（最佳）附加项后，可以轻松扩展其他解决方案条件表。