如何解决MySQL应该使用哪个查询语句?
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。
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。
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