mysql - 年龄组之间的sql

Question

希望你能帮帮我!

我有以下数据库:

country | Date_of_birth
-----------------------
france  | 1980-07-01
spain   | 1978-03-23
greece  | 1981-05-05
germany | 1974-08-11

我试图得到这个结果:

country | 13 - 17 | 25 - 45 | 65 - 75
-------------------------------------
france  |         |     1   |
spain   |         |     1   |
greece  |         |     1   |

到目前为止我想出的查询:

SELECT SUM( IF( age BETWEEN 13 AND 17 , 1, 0)) AS '13 - 17', 
       SUM( IF( age BETWEEN 25 AND 45 , 1, 0)) AS '25 - 45', 
       SUM( IF( age BETWEEN 65 AND 75 , 1, 0)) AS '65 - 75'
FROM (SELECT TIMESTAMPDIFF( YEAR, Date_of_birth, CURDATE()) AS age, country FROM data
) AS test
GROUP BY country
HAVING country IN ("france","greece,"spain")

结果:

 13 - 17 | 25 - 45 | 65 - 75
----------------------------
         |     1   |
         |     1   |
         |     1   |

知道我如何在开头获得“国家/地区”列吗？

提前致谢!

Answer 1

Having 仅适用于聚合 列。你想要一个简单的 where:

SELECT 
       country,
       SUM(age BETWEEN 13 AND 17) AS '13 - 17', 
       SUM(age BETWEEN 25 AND 45) AS '25 - 45', 
       SUM(age BETWEEN 65 AND 75) AS '65 - 75'
FROM (SELECT TIMESTAMPDIFF( YEAR, Date_of_birth, CURDATE()) AS age, country FROM data
      ) AS test
WHERE country IN ('france', 'greece', 'spain')
GROUP BY country

还要注意查询的简化:在 mysql 中 true 是 1 而 false 是 0，所以您可以简单地对条件求和 - 您不需要 case。

此外，您有一个语法错误 - 您需要在国家/地区值周围加上单引号。