Yisu cloud 2022-06-23 18:12:32 阅读数:198
This article mainly introduces Hive How to convert the date format , The content is detailed and easy to understand , The operation is simple and fast , It has certain reference value , I believe that after reading this article Hive How to convert the date format to the article will be fruitful , Let's have a look .
Date calculation is often involved in business data retrieval , But there are often different date formats stored in the database , Some store time stamps 、 Some are strings and so on , At this time, it needs to be transformed to extract accurate data , What is introduced here is hive The functions inside , The following contents are frequently used by the data requirements of the business
unix The time stamp is from 1970 year 1 month 1 Japan （UTC/GMT At midnight ） The number of seconds to start , Leap seconds not considered , It's usually 10 An integer
String date Such as ：'2021-10-21 19:25:50','2021-10-21 20:25:50.0','2021-10-21 20:25'
Time stamp ---> Normal date format
Get the current timestamp
Change the timestamp to the normal date
select from_unixtime(unix_timestamp(),'yyyy-MM-dd hh:mm:ss') as dt
Sometimes an integer containing milliseconds is stored in the business , It needs to be converted to seconds first
select from_unixtime(cast(create_time/1000 as bigint),'yyyyMMdd') as dt
String date If the database is stored in the format of ："yyyy-MM-dd hh:mm:ss"
Intercept the date part
select substr('2021-10-22 17:34:56',1,10)2021-10-22
String cast , Get date
select to_date('2021-10-22 17:34:56')2021-10-22
It can also be done through date_format Realization
select date_format('2021-10-22 17:34:56','yyyy-MM-dd')2021-10-22
Current system date
The current date
Compare the string date with the current system date , This is often useful in business
select substr('2021-10-22 17:34:56',1,10)>current_date()false
The day before / Yesterday,
The day before 12 spot / Yesterday, 12 spot It is used to compare with the intercepted string date in the business
select concat(date_format(date_sub(current_date(),1),'yyyy-MM-dd'),' ','12');2021-10-21 12
Last month /30 God
The first day of the month It is often used in business to calculate the daily performance data of the current month
Date format conversion yyyyMMdd--->yyyy-MM-dd
Days between two dates
select datediff('2021-10-22', '2021-10-01');21
About “Hive How to convert date format ” That's all for this article , Thank you for reading ！ I'm sure you're right “Hive How to convert date format ” Knowledge has a certain understanding , If you want to learn more , Welcome to the Yisu cloud industry information channel .
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