题解 | #查看不同年龄段的用户明细#

** 主要考察利用case when多条件筛选函数的利用，**
(case when age>=25 then "25岁以上"
when age between 20 and 24 then "20-24岁"
when age<20 then "20岁以下"
else "其他" end) as age_cnt

SELECT device_id,
       gender,
       (case when age>=25 then "25岁以上" 
             when age between 20 and 24 then "20-24岁"
             when age<20 then "20岁以下"
             else "其他" end) as age_cnt
FROM user_profile;