Question

标题解释了我的整个问题。这是查询：

select
date_format(now(), '%Y') - date_format(date_of_birth, '%Y') age,
IF(date_format(now(), '%Y') - date_format(date_of_birth, '%Y') < 18,
  'Under 18',
  IF(date_format(now(), '%Y') - date_format(date_of_birth, '%Y') <= 24,
    '19 to 24',
    IF(date_format(now(), '%Y') - date_format(date_of_birth, '%Y') <= 34,
      '25 to 34',
      'Over 34'))) age_range
from customer

Answer 1

看起来很适合CASE。

应该看起来像以下（未经测试）：

select
date_format(now(), '%Y') - date_format(date_of_birth, '%Y') age, 
        CASE age 
          WHEN age < 18 THEN 'Under 18'
          WHEN age <= 24 THEN '19 - 24'
          WHEN age <= 34 THEN '25 - 34'
          ELSE 'Over 34'
        END CASE AS age_range
from customer

Answer 2

我建议使用case和嵌套查询的组合 - 类似于：

select s.age,
       case when s.age < 18 then 'Under 18'
            when s.age <= 24 then '19 to 24'
            when s.age <= 34 then '25 to 34'
            else 'Over 34'
       end case as age_range
from (select date_format(now(), '%Y') - date_format(date_of_birth, '%Y') as age
      from customer) s

是否有更优雅，或至少更干的方式来编写这一系列的SQL IF？

2 个答案: