牛客刷SQL
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SQL27 查看不同年龄段的用户明细
描述
题目:现在运营想要将用户划分为20岁以下,20-24岁,25岁及以上三个年龄段,分别查看不同年龄段用户的明细情况,请取出相应数据。(注:若年龄为空请返回其他。)
示例:user_profile
id device_id gender age university gpa active_days_within_30 question_cnt answer_cnt 1 2138 male 21 北京大学 3.4 7 2 12 2 3214 male 复旦大学 4 15 5 25 3 6543 female 20 北京大学 3.2 12 3 30 4 2315 female 23 浙江大学 3.6 5 1 2 5 5432 male 25 山东大学 3.8 20 15 70 6 2131 male 28 山东大学 3.3 15 7 13 7 4321 male 26 复旦大学 3.6 9 6 52 根据示例,你的查询应返回以下结果:
device_id gender age_cut 2138 male 20-24岁 3214 male 其他 6543 female 20-24岁 2315 female 20-24岁 5432 male 25岁及以上 2131 male 25岁及以上 4321 male 25岁及以上 示例1
输入:
drop table if exists `user_profile`; drop table if exists `question_practice_detail`; CREATE TABLE `user_profile` ( `id` int NOT NULL, `device_id` int NOT NULL, `gender` varchar(14) NOT NULL, `age` int , `university` varchar(32) NOT NULL, `gpa` float, `active_days_within_30` int , `question_cnt` int , `answer_cnt` int ); CREATE TABLE `question_practice_detail` ( `id` int NOT NULL, `device_id` int NOT NULL, `question_id`int NOT NULL, `result` varchar(32) NOT NULL ); CREATE TABLE `question_detail` ( `id` int NOT NULL, `question_id`int NOT NULL, `difficult_level` varchar(32) NOT NULL ); INSERT INTO user_profile VALUES(1,2138,'male',21,'北京大学',3.4,7,2,12); INSERT INTO user_profile VALUES(2,3214,'male',null,'复旦大学',4.0,15,5,25); INSERT INTO user_profile VALUES(3,6543,'female',20,'北京大学',3.2,12,3,30); INSERT INTO user_profile VALUES(4,2315,'female',23,'浙江大学',3.6,5,1,2); INSERT INTO user_profile VALUES(5,5432,'male',25,'山东大学',3.8,20,15,70); INSERT INTO user_profile VALUES(6,2131,'male',28,'山东大学',3.3,15,7,13); INSERT INTO user_profile VALUES(7,4321,'male',28,'复旦大学',3.6,9,6,52); INSERT INTO question_practice_detail VALUES(1,2138,111,'wrong'); INSERT INTO question_practice_detail VALUES(2,3214,112,'wrong'); INSERT INTO question_practice_detail VALUES(3,3214,113,'wrong'); INSERT INTO question_practice_detail VALUES(4,6543,111,'right'); INSERT INTO question_practice_detail VALUES(5,2315,115,'right'); INSERT INTO question_practice_detail VALUES(6,2315,116,'right'); INSERT INTO question_practice_detail VALUES(7,2315,117,'wrong'); INSERT INTO question_practice_detail VALUES(8,5432,117,'wrong'); INSERT INTO question_practice_detail VALUES(9,5432,112,'wrong'); INSERT INTO question_practice_detail VALUES(10,2131,113,'right'); INSERT INTO question_practice_detail VALUES(11,5432,113,'wrong'); INSERT INTO question_practice_detail VALUES(12,2315,115,'right'); INSERT INTO question_practice_detail VALUES(13,2315,116,'right'); INSERT INTO question_practice_detail VALUES(14,2315,117,'wrong'); INSERT INTO question_practice_detail VALUES(15,5432,117,'wrong'); INSERT INTO question_practice_detail VALUES(16,5432,112,'wrong'); INSERT INTO question_practice_detail VALUES(17,2131,113,'right'); INSERT INTO question_practice_detail VALUES(18,5432,113,'wrong'); INSERT INTO question_practice_detail VALUES(19,2315,117,'wrong'); INSERT INTO question_practice_detail VALUES(20,5432,117,'wrong'); INSERT INTO question_practice_detail VALUES(21,5432,112,'wrong'); INSERT INTO question_practice_detail VALUES(22,2131,113,'right'); INSERT INTO question_practice_detail VALUES(23,5432,113,'wrong'); INSERT INTO question_detail VALUES(1,111,'hard'); INSERT INTO question_detail VALUES(2,112,'medium'); INSERT INTO question_detail VALUES(3,113,'easy'); INSERT INTO question_detail VALUES(4,115,'easy'); INSERT INTO question_detail VALUES(5,116,'medium'); INSERT INTO question_detail VALUES(6,117,'easy');复制输出:
2138|male|20-24岁 3214|male|其他 6543|female|20-24岁 2315|female|20-24岁 5432|male|25岁及以上 2131|male|25岁及以上 4321|male|25岁及以上
SELECT device_id,gender , case
when age<20 then '20岁以下'
when age>=20 && age<=24 then '20-24岁'
when age>24 then '25岁及以上'
else '其他'
end as age_cnt
from user_profile;