Mysql 使用SQL选择年龄组

这是关于这一问题的后续问题。我在MySQL数据库中为用户的生日设置了一个日期字段，并使用以下查询获取年龄：

选择 ROUNDDATEDIFF 现在选择日期， 以生日为日期 /365岁，0岁 来自成员 现在，我需要选择不同年龄组的人数。例如，我需要知道13-17岁、18-21岁、22-25岁、26-35岁、36-50岁、51-MAX年龄组的人数

使用MySQL可能吗

我想到过工会，就像这样：

SELECT 
    ROUND(DATEDIFF(
        Cast((SELECT NOW()) as Date),
        Cast(birthday as Date)
    ) / 365, 0) as age,
    1 as agegroup
FROM member WHERE age >=13 AND age <=17

UNION

SELECT 
    ROUND(DATEDIFF(
        Cast((SELECT NOW()) as Date),
        Cast(birthday as Date)
    ) / 365, 0) as age
    2 as agegroup
FROM member WHERE age >=18 AND age <=21

SELECT
    SUM(CASE WHEN age < 10 THEN 1 ELSE 0 END) AS under10,
    SUM(CASE WHEN 10<age AND age <19 THEN 1 ELSE 0 END) AS age10to19,
    .
    .
    .
FROM table

---

但那将是漫长而丑陋的。一定有更好的办法

如果您将年龄作为表中的一列，您可以这样做：

SELECT 
    ROUND(DATEDIFF(
        Cast((SELECT NOW()) as Date),
        Cast(birthday as Date)
    ) / 365, 0) as age,
    1 as agegroup
FROM member WHERE age >=13 AND age <=17

UNION

SELECT 
    ROUND(DATEDIFF(
        Cast((SELECT NOW()) as Date),
        Cast(birthday as Date)
    ) / 365, 0) as age
    2 as agegroup
FROM member WHERE age >=18 AND age <=21

select  AgeGroup
,       count(*)
from    (
        select  case
                when  age between 13 and 17 then 1
                when  age between 18 and 21 then 2
                ...
                end as AgeGroup
        from    (
                SELECT  ROUND(DATEDIFF(Cast(NOW() as Date),
                            Cast(birthday as Date)) / 365, 0) as age
                FROM    YourTable
                ) as SubQueryAlias
        ) as SubQueryAlias2
group by
        AgeGroup

SELECT
    SUM(CASE WHEN age < 10 THEN 1 ELSE 0 END) AS under10,
    SUM(CASE WHEN 10<age AND age <19 THEN 1 ELSE 0 END) AS age10to19,
    .
    .
    .
FROM table

---

可能会有一些小的变化，因为年龄不在它自己的列中，或者如果你想要额外的或不同的范围。我相信你能自己解决

如果您将年龄作为表中的一列，您可以这样做：

SELECT 
    ROUND(DATEDIFF(
        Cast((SELECT NOW()) as Date),
        Cast(birthday as Date)
    ) / 365, 0) as age,
    1 as agegroup
FROM member WHERE age >=13 AND age <=17

UNION

SELECT 
    ROUND(DATEDIFF(
        Cast((SELECT NOW()) as Date),
        Cast(birthday as Date)
    ) / 365, 0) as age
    2 as agegroup
FROM member WHERE age >=18 AND age <=21

SELECT
    SUM(CASE WHEN age < 10 THEN 1 ELSE 0 END) AS under10,
    SUM(CASE WHEN 10<age AND age <19 THEN 1 ELSE 0 END) AS age10to19,
    .
    .
    .
FROM table

---

可能会有一些小的变化，因为年龄不在它自己的列中，或者如果你想要额外的或不同的范围。我相信你能自己解决

另一种可能的解决方案：-

SELECT  AgeRange.MinAge, AgeRange.MaxAge, COUNT(*)
FROM    
(
    SELECT 13 AS MinAge, 17 AS MaxAge
    UNION SELECT 18, 21
    UNION SELECT 22, 25
    UNION SELECT 26, 35
    UNION SELECT 36, 50
    UNION SELECT 51, 9999
) AgeRange
INNER JOIN YourTable
ON ROUND(DATEDIFF(CAST(NOW() as DATE), CAST(birthday as DATE)) / 365, 0) BETWEEN AgeRange.MinAge AND AgeRange.MaxAge 
GROUP BY AgeRange.MinAge, AgeRange.MaxAge

---

如果需要，可以更容易地进行扩展，或者使用表格中的日期范围，以便用户在需要时可以轻松地更新生成的报告。

另一种可能的解决方案：-

SELECT  AgeRange.MinAge, AgeRange.MaxAge, COUNT(*)
FROM    
(
    SELECT 13 AS MinAge, 17 AS MaxAge
    UNION SELECT 18, 21
    UNION SELECT 22, 25
    UNION SELECT 26, 35
    UNION SELECT 36, 50
    UNION SELECT 51, 9999
) AgeRange
INNER JOIN YourTable
ON ROUND(DATEDIFF(CAST(NOW() as DATE), CAST(birthday as DATE)) / 365, 0) BETWEEN AgeRange.MinAge AND AgeRange.MaxAge 
GROUP BY AgeRange.MinAge, AgeRange.MaxAge

---

如果需要，可能更容易扩展，或者移动到使用表格中的日期范围，以便用户可以在需要时方便地更新生成的报告。

表格是问题中OP显示的子选项，您也有一个拼写错误：否则9应该是其他0表格是问题中OP显示的子选项，您也有一个拼写错误：否则9应该是其他0