HiveSQL经典面试题（建议点赞收藏）

目录
经典面试系列
每科成绩都大于80分的学生信息
连续登录问题
行列转换问题
留存问题：看当天登录后第N天是否登录
TopN问题
累计计算问题
HSQL进阶版
 直播间在线最大人数
SQL循环
计算中位数
产生连续数值

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经典面试系列

• 每科成绩都大于80分的学生信息
  
  
  • 建表+初始化
    1. --创建表scdn_student_score_test 并且初始化三个学生成绩
    2. create table hdw_tmp_dev.scdn_student_score_test as
    3. select '张三' as name,'数学' as subject ,'80' as score
    4. union all
    5. select '张三' as name,'语文' as subject ,'90' as score
    6. union all
    7. select '张三' as name,'英语' as subject ,'90' as score
    8. union all
    9. select '李四' as name,'数学' as subject ,'90' as score
    10. union all
    11. select '李四' as name,'语文' as subject ,'90' as score
    12. union all
    13. select '李四' as name,'英语' as subject ,'70' as score
    14. union all
    15. select '王五' as name,'数学' as subject ,'90' as score
    16. union all
    17. select '王五' as name,'语文' as subject ,'90' as score
    18. union all
    19. select '王五' as name,'英语' as subject ,'50' as score
    20. --查询结果显示
    21. | scdn_student_score_test.name  | scdn_student_score_test.subject  | scdn_student_score_test.score  |
    22. +-------------------------------+----------------------------------+--------------------------------+
    23. | 张三                            | 数学                               | 80                             |
    24. | 张三                            | 语文                               | 90                             |
    25. | 张三                            | 英语                               | 90                             |
    26. | 李四                            | 数学                               | 90                             |
    27. | 李四                            | 语文                               | 90                             |
    28. | 李四                            | 英语                               | 70                             |
    29. | 王五                            | 数学                               | 90                             |
    30. | 王五                            | 语文                               | 90                             |
    31. | 王五                            | 英语                               | 50                             |
    32. +-------------------------------+----------------------------------+---------------------
    34. --求所有学科成绩都大于等于80分的学生姓名

    复制代码
  • 思路一（头脑转换）：所有问题找最小（最大）
    1. select
    2.     t1.name
    3.     ,t1.min_score
    4. from
    5.     (
    6.         select
    7.             name
    8.             ,min(score)  as min_score
    9.         from hdw_tmp_dev.scdn_student_score_test
    10.         group by name
    11.     ) as t1 --求出最小的成绩
    12. where t1.min_score >=80 --最小成绩大于等于80，则这个学生的所有成绩都会大于等于80

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  • 执行效果
    
    
    
  • 思路二（巧用左关联举行筛选）：
    1. select
    2.     t1.name
    3. from
    4. (
    5.     select
    6.         name
    7.     from hdw_tmp_dev.scdn_student_score_test
    8.     group by name
    9. ) as t1
    10. left join
    11. (
    12.     select
    13.         name
    14.     from hdw_tmp_dev.scdn_student_score_test
    15.     where score <80
    16.     group by name
    17. ) as t2 on t1.name = t2.name
    18. where t2.name is null

    复制代码
  
  
• 连续登录问题
  
  
  • 建表+初始化
    1. create table hdw_tmp_dev.csdn_user_login_test as
    2. select 'xiaoming' as user_name,'2024-01-01' as login_date
    3. union all
    4. select 'xiaoming' as user_name,'2024-01-02' as login_date
    5. union all
    6. select 'xiaoming' as user_name,'2024-01-03' as login_date
    7. union all
    8. select 'xiaoming' as user_name,'2024-01-04' as login_date
    9. union all
    10. select 'xiaoming' as user_name,'2024-01-05' as login_date
    11. union all
    12. select 'dahuang' as user_name,'2024-01-02' as login_date
    13. union all
    14. select 'dahuang' as user_name,'2024-01-03' as login_date
    15. union all
    16. select 'dahuang' as user_name,'2024-01-04' as login_date
    17. union all
    18. select 'dahuang' as user_name,'2024-01-05' as login_date
    19. union all
    20. select 'lucky_dog' as user_name,'2024-01-01' as login_date
    21. union all
    22. select 'lucky_dog' as user_name,'2024-01-03' as login_date
    23. union all
    24. select 'lucky_dog' as user_name,'2024-01-04' as login_date
    25. union all
    26. select 'lucky_dog' as user_name,'2024-01-05' as login_date

    复制代码
  • Sql参考
    1. select
    2.     t2.user_name
    3.     ,t2.date_begin_flag
    4.     ,count(1) as max_login_days
    5. from
    6. (
    7.     select
    8.         t1.user_name
    9.         ,t1.login_date
    10.         ,date_sub(date(login_date),t1.rn) as date_begin_flag
    11.     from
    12.     (
    13.         select
    14.             user_name
    15.             ,login_date
    16.             ,row_number()over(partition by user_name order by login_date) as rn
    17.         from hdw_tmp_dev.csdn_user_login_test
    18.     ) as t1
    19. ) as t2  
    20. group by t2.user_name
    21.     ,t2.date_begin_flag

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  • 执行过程+效果
    
    
    
    
  
  
• 行列转换问题
  
  
  • 建表+初始化：参考问题一的表
    1. | t1.name              | t1.subject             | t1.score  |
    2. +-------------------------------+----------------------------------+-----------------+
    3. | 张三                 | 数学                    | 80                             |
    4. | 张三                 | 语文                    | 90                             |
    5. | 张三                 | 英语                    | 90                             |
    6. | 李四                 | 数学                    | 90                             |
    7. | 李四                 | 语文                    | 90                             |
    8. | 李四                 | 英语                    | 70                             |
    9. | 王五                 | 数学                    | 90                             |
    10. | 王五                 | 语文                    | 90                             |
    11. | 王五                 | 英语                    | 50                             |
    12. +-------------------------------+----------------------------------+------------------

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  • 行专列Sql参考
    1. select
    2.     name
    3.     ,max(case when subject = '数学' then score end) as math_score
    4.     ,max(case when subject = '语文' then score end) as china_score
    5.     ,max(case when subject = '英语' then score end) as english_score
    6. from hdw_tmp_dev.scdn_student_score_test
    7. group by name

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  • 行专列执行效果
    
    
    
  • 列转行：可以参考建表初始化语句（union all）
    1. select
    2.     name
    3.     ,collect_set(subject)  as subject_set
    4. from hdw_tmp_dev.scdn_student_score_test
    5. group by name

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  • 每个学生选课效果（多行变一行）：
    
    
    
  •  将上面的效果睁开（一行变多行）数据准备：
    
    1. create table hdw_tmp_dev.scdn_student_score_test_collect as
    2. select 'zhangsan' as name ,'"数学","语文","英语"' as subject_list
    3. union all
    4. select 'lisi' as name ,'"美术","生物","物理"' as subject_list
    5. union all
    6. select 'wangwu' as name ,'"计算机","日语","韩语"' as subject_list

    复制代码
  • 炸开代码
    1. select
    2.     name
    3.     ,subject_list
    4.     ,subject_name
    5. from hdw_tmp_dev.scdn_student_score_test_collect
    6. lateral view explode(split(subject_list,',')) extend_sub as subject_name

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  • 效果
    
    
    
  
  
• 留存问题：看当天登录后第N天是否登录
  
  
  • 建表+初始化：参照连续登录表
    
  • Sql参考
    1. --方案一：利用lead(日期，N)是否等于 当天登录实践+N天
    2. select
    3.     t1.user_name
    4.     ,t1.logon_date
    5.     ,case when lead1_logon_date = date_add(logon_date,1) then '1天留存' end as 1day_remain
    6.     ,case when lead3_logon_date = date_add(logon_date,3) then '3天留存' end as 3day_remain
    7. from
    8. (
    9.     select
    10.         user_name
    11.         ,logon_date
    12.         ,lead(user_name,1)over(partition by user_name order by logon_date) as lead1_user_name
    13.         ,lead(logon_date,1)over(partition by user_name order by logon_date) as lead1_logon_date
    14.         ,lead(user_name,3)over(partition by user_name order by logon_date) as lead3_user_name
    15.         ,lead(logon_date,3)over(partition by user_name order by logon_date) as lead3_logon_date
    16.     from hdw_tmp_dev.csdn_user_logon_test
    17. ) as t1
    18. --方案二：
    19. select
    20.     t2.first_log_date       as first_log_date
    21.     ,count(t2.user_id)      as new_user_cnt --新用户数
    22.     ,count(t3.user_id)      as next_user_id --次日回访用户数
    23.     ,count(t4.user_id)      as 30_user_id   --30天回访用户数
    24.     ,count(t3.user_id)/count(t2.user_id)    as next_back_rate --次日回访率
    25.     ,count(t4.user_id)/count(t2.user_id)    as 30_back_rate   --30天回访率
    26. from
    27. (
    28.     select
    29.         first_log_date
    30.         ,user_id
    31.         ,date_add(first_log_date,1)  as next_log_date
    32.         ,date_add(first_log_date,29) as 30_log_date
    33.     from
    34.     (
    35.         select
    36.             user_id
    37.             ,log_time
    38.             ,first_value(date(log_time))over(partition by user_id) as first_log_date
    39.         from user_log
    40.     ) as t1
    41.     group by first_log_date
    42.         ,user_id
    43. ) as t2
    44. left join
    45. (
    46.     select
    47.         user_id
    48.         ,date(log_date) as log_date  
    49.     from user_log
    50.     group by user_id
    51.         ,date(log_date) as log_date
    52. ) as t3 on t2.user_id = t2.user_id and t2.next_log_date = t3.log_date
    53. left join
    54. (
    55.     select
    56.         user_id
    57.         ,date(log_date) as log_date  
    58.     from user_log
    59.     group by user_id
    60.         ,date(log_date) as log_date
    61. ) as t4 on t2.user_id = t4.user_id and t2.30_log_date = t4.log_date
    62. group by t2.first_log_date

    复制代码
  • 方案一执行效果
    
    
    
  
  
• TopN问题
  
  
  • 建表+初始化
    1. create table hdw_tmp_dev.scdn_student_score_test1 as
    2. select '张三' as name,'数学' as subject ,'80' as score
    3. union all
    4. select '张三' as name,'语文' as subject ,'90' as score
    5. union all
    6. select '张三' as name,'英语' as subject ,'90' as score
    7. union all
    8. select '李四' as name,'数学' as subject ,'90' as score
    9. union all
    10. select '李四' as name,'语文' as subject ,'90' as score
    11. union all
    12. select '李四' as name,'英语' as subject ,'70' as score
    13. union all
    14. select '王五' as name,'数学' as subject ,'90' as score
    15. union all
    16. select '王五' as name,'语文' as subject ,'90' as score
    17. union all
    18. select '王五' as name,'英语' as subject ,'50' as score
    19. union all
    20. select '小明' as name,'数学' as subject ,'88' as score
    21. union all
    22. select '小明' as name,'语文' as subject ,'99' as score
    23. union all
    24. select '小明' as name,'英语' as subject ,'77' as score
    25. union all
    26. select '小文' as name,'数学' as subject ,'66' as score
    27. union all
    28. select '小文' as name,'语文' as subject ,'89' as score
    29. union all
    30. select '小文' as name,'英语' as subject ,'90' as score

    复制代码
  • Sql参考：求每科前三名对应的人员的成绩单
    1. select
    2.     *
    3. from
    4. (
    5.     select
    6.         name
    7.         ,subject
    8.         ,score
    9.         ,row_number()over(partition by subject order by score desc) as rn
    10.     from hdw_tmp_dev.scdn_student_score_test1
    11. ) as t1
    12. where rn<=3

    复制代码
  • 执行效果
    
    
    
  
  
• 累计计算问题
  
  
  • 建表+初始化
    1. create table hdw_tmp_dev.user_sale_date as
    2. select '001' as user_id,'2024-02-01' as sale_date, 100 as amount
    3. union all
    4. select '001' as user_id,'2024-02-02' as sale_date, 200 as amount
    5. union all
    6. select '001' as user_id,'2024-02-03' as sale_date, 300 as amount
    7. union all
    8. select '001' as user_id,'2024-02-04' as sale_date, 400 as amount
    9. union all
    10. select '001' as user_id,'2024-02-05' as sale_date, 500 as amount
    11. union all
    12. select '001' as user_id,'2024-02-06' as sale_date, 600 as amount

    复制代码
  • SQL逻辑
    1. select
    2.     user_id
    3.     ,sale_date
    4.     ,amount
    5.     ,sum(amount)over(partition by user_id order by sale_date) as accuma_amount --按日期逐渐累加
    6.     ,sum(amount)over(partition by user_id) as total_amount --按人汇总
    7.     ,avg(amount)over(partition by user_id) as avg_amount --安人平均每天
    8.     ,max(amount)over(partition by user_id) as max_amount --单日最大销售
    9.     ,min(amount)over(partition by user_id) as min_amount --单日最小销售
    10. from hdw_tmp_dev.user_sale_date

    复制代码
  • 效果展示
    
    
    
  
  

HSQL进阶版

•  直播间在线最大人数
  
  
  • 建表+初始化
    1. create table hdw_tmp_dev.csdn_user_login_time_detail as
    2. select '001' as user_id,'2024-02-01 10:00:00' as begin_time,'2024-02-01 12:00:00' as end_time
    3. union all
    4. select '002' as user_id,'2024-02-01 11:00:00' as begin_time,'2024-02-01 13:00:00' as end_time
    5. union all
    6. select '003' as user_id,'2024-02-01 11:00:00' as begin_time,'2024-02-01 14:00:00' as end_time
    7. union all
    8. select '004' as user_id,'2024-02-01 15:00:00' as begin_time,'2024-02-01 16:00:00' as end_time

    复制代码
  • SQL逻辑
    1. select
    2.     t1.user_id
    3.     ,t1.time1
    4.     ,t1.flag
    5.     ,sum(flag)over(order by t1.time1) as user_cnt
    6. from
    7. (
    8.     select
    9.         user_id
    10.         ,begin_time as time1
    11.         ,1    as flag
    12.     from hdw_tmp_dev.csdn_user_login_time_detail
    13.     union all
    14.     select
    15.         user_id
    16.         ,end_time
    17.         ,-1    as flag
    18.     from hdw_tmp_dev.csdn_user_login_time_detail
    19. ) as t1

    复制代码
  • 效果展示
    
    
    
  
  
• SQL循环
  
  
  • 建表+初始化
    1. create table hdw_tmp_dev.cycle_1 as
    2. select '1011' as a
    3. union all
    4. select '0101' as a

    复制代码
  • SQL逻辑
    1. select  
    2.         a,
    3.         concat_ws(",",collect_list(cast(index  as  string)))  as  res
    4. from  (
    5.         select  
    6.                 a,
    7.                 index+1  as  index,
    8.                 chr
    9.         from  (
    10.                 select  
    11.                         a,
    12.                         concat_ws(",",substr(a,1,1),substr(a,2,1),substr(a,3,1),substr(a,-1))  str
    13.                 from  hdw_tmp_dev.cycle_1 as t8
    14.         )  tmp1
    15.         lateral  view  posexplode(split(str,","))  t  as  index,chr
    16.         where  chr  =  "1"
    17. )  tmp2
    18. group  by  a;

    复制代码
  • 效果展示
    
    
    
  
  
• 计算中位数
  
  
  • 建表+初始化:
    1. create table hdw_tmp_dev.user_sale_date as
    2. select '001' as user_id,'2024-02-01' as sale_date, 100 as amount
    3. union all
    4. select '001' as user_id,'2024-02-02' as sale_date, 200 as amount
    5. union all
    6. select '001' as user_id,'2024-02-03' as sale_date, 300 as amount
    7. union all
    8. select '001' as user_id,'2024-02-04' as sale_date, 400 as amount
    9. union all
    10. select '001' as user_id,'2024-02-05' as sale_date, 500 as amount
    11. union all
    12. select '001' as user_id,'2024-02-06' as sale_date, 600 as amount

    复制代码
  • SQL逻辑
    1. select
    2.     t1.user_id
    3.     ,t1.sale_date
    4.     ,t1.amount
    5.     ,avg(t1.amount)over(partition by t1.user_id) as zhongwenshu
    6. from
    7. (
    8.     select
    9.         user_id
    10.         ,sale_date
    11.         ,amount
    12.         ,row_number()over(partition by user_id order by amount) as rn
    13.     from hdw_tmp_dev.user_sale_date
    14. ) as t1
    15. left join
    16. (
    17.     select
    18.         user_id
    19.         ,count(1) as cnt
    20.     from hdw_tmp_dev.user_sale_date
    21.     group by user_id
    22. ) as t2 on t1.user_id = t2.user_id
    23. where t1.rn in (cnt/2,(cnt+1)/2,cnt/2+1)
    24. --总个数为奇数命中(cnt+1)/2；总个数为偶数命中：cnt/2,cnt/2+1，两数相加求平均值

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  • 效果展示
    
    
    
  
  
• 产生连续数值
  
  
  • SQL逻辑
    1. --产生1到10的连续数据
    2. select
    3.     start_id + pos  as  id
    4.     ,pos
    5.     ,val
    6. from(
    7.     select
    8.         1   as  start_id,
    9.         10  as  end_id
    10. )  m  lateral  view  posexplode(split(space(end_id - start_id),''))  t  as  pos,  val
    11. --方案二
    12. select
    13.     row_number()  over()  as  id
    14. from   
    15.     (select  split(space(99), '') as  x)  t
    16. lateral  view
    17. explode(x)  ex;

    复制代码
  • 效果展示
    
    
    
  
  

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