错误答案:
select device_id,gender, case when age <20 then "20岁以下"
when age <=20 and age<=24 then "20-24岁"
when age >=25 then "25岁及以上"
when age is null then "其他"
end age_cut
FROM user_profile
正确答案:
select device_id,gender, case when age <20 then "20岁以下"
when age between 20 and 24 then "20-24岁"
when age >=25 then "25岁及以上"
when age is null then "其他"
end age_cut
FROM user_profile
在判断20-24阶段时,使用 age <=20 and age<=24 时结果不正确,
但使用 age between 20 and 24 时结果就正确。