Question

这是一些信用卡记录，我需要查找具有最大卡到期日期的年份。由于日期不是YYYY/MM/DD格式，因此在模式中，我已将日期定义为“字符串”类型

Card Type Full Name,Card Holder's Name,Issue Date,Expiry Date,Card PIN

Discover,Brenda D Peterson,01/2017,01/2022,1998
Diners Club International,Dawn U Reese,12/2015,12/2013,3915 
Diners Club International,Helen P Perry,02/2007,02/2020,2319
American Express,Christine E Kim,08/2011,08/2013,9017

Answer 1

此查询将为您提供记录数最多的年份。

select 
   substr(expiry_date, instr(expiry_date, '/')+1) as expiry_year,
   count(*) as cnt
from customers
group by substr(expiry_date, instr(expiry_date, '/')+1)
order by cnt desc
limit 1;

在这种情况下，有可能超过1年的相同数量的卡在该年到期，您可以在下面的查询中使用

select 
   substr(expiry_date, instr(expiry_date, '/')+1) as expiry_year
from customers
having count(*) = (
   select max(cnt) from (
      select 
         substr(expiry_date, instr(expiry_date, '/')+1) as expiry_year,
         count(*) as cnt
      from customers
         group by substr(expiry_date, instr(expiry_date, '/')+1)
   )t
);

查找Hive中一年最多出现的次数

1 个答案: