hive时间函数的使用
时间函数的变形
select
day -- 时间
,date_add(day,1 - dayofweek(day)) as week_first_day -- 本周第一天_周日
,date_add(day,7 - dayofweek(day)) as week_last_day -- 本周最后一天_周六
,date_add(day,1 - case when dayofweek(day) = 1 then 7 else dayofweek(day) - 1 end) as week_first_day -- 本周第一天_周一
,date_add(next_day(day,'MO'),-7) as week_first_day -- 本周第一天_周一;
,date_add(day,7 - case when dayofweek(day) = 1 then 7 else dayofweek(day) - 1 end) as week_last_day -- 本周最后一天_周日
,next_day(day,'TU') as next_tuesday -- 当前日期的下个周二
,trunc(day,'MM') as month_first_day -- 当月第一天
,date_sub(current_date,dayofmonth(current_date)-1) as month_first_day1 -- 当月第一天
,add_months(date_sub(current_date,dayofmonth(current_date)-1),1) as next_month_first_day -- 下月第一天
,last_day(day) as month_last_day -- 当月最后一天
,to_date(concat(year(day),'-',lpad(ceil(month(day)/3) * 3 -2,2,0),'-01')) as season_first_day -- 当季第一天
,last_day(to_date(concat(year(day),'-',lpad(ceil(month(day)/3) * 3,2,0),'-01'))) as season_last_day -- 当季最后一天
,trunc(day,'YY') as year_first_day -- 当年第一天
,last_day(add_months(trunc(day,'YY'),12)) as year_last_day -- 当年最后一天
,weekofyear(day) as weekofyear -- 当年第几周
,second(day) as second -- 秒钟
,minute(day) as minute -- 分钟
,hour(day) as hour -- 小时
,day(day) as day -- 日期
,month(day) as month -- 月份
,lpad(ceil(month(day)/3),2,0) as season -- 季度
,year(day) as year -- 年份
from (
select '2021-01-12 01:01:01' as day union all
select '2021-02-12 02:03:04' as day union all
select '2021-03-12 03:05:07' as day union all
select '2021-04-12 04:07:10' as day union all
select '2021-05-12 05:09:13' as day union all
select '2021-06-12 06:11:16' as day union all
select '2021-07-12 07:13:19' as day union all
select '2021-08-12 08:15:22' as day union all
select '2021-09-12 09:17:25' as day union all
select '2021-10-12 10:19:28' as day union all
select '2021-11-12 11:21:31' as day union all
select '2021-12-12 12:23:34' as day
) t1
;
1、获取当前时间戳
select unix_timestamp() ;
2.1、获取当前时间1（时分秒）
select current_timestamp()
2.2、获取当前时间2
SELECT from_unixtime(unix_timestamp());
3、获取当前时间(年月日)
select current_date()
4、日期差值：datediff(结束日期，开始日期)，返回结束日期减去开始日期的天数。
select datediff(CURRENT_DATE,'2021-01-01') as datediff;
5、日期加减：date_add（时间，增加天数），返回值为时间天+增加天的日期；date_sub（时间，减少天数），返回日期减少天后的日期。
select date_add(current_date,365) as dateadd;
6、时间差：两个日期之间的小时差
select (hour('2021-12-27 10:00:00')-hour('2021-12-25 12:00:00')+(datediff('2021-12-27 10:00:00','2021-12-25 12:00:00'))*24) as hour_subValue;
或者先将年月日时分秒的格式转为 时间戳格式后再进行加减
分钟数：(UNIX_TIMESTAMP(service_end_time) - UNIX_TIMESTAMP(service_start_time))/60)
小时数： ((UNIX_TIMESTAMP(service_end_time) - UNIX_TIMESTAMP(service_start_time))/60) ) /60
9、获取年、月、日、小时、分钟、秒、当年第几周
select
year('2021-12-01 10:00:00') as year
,month('2021-12-01 10:00:00') as month
,day('2021-12-01 10:00:00') as day
,hour('2021-12-01 10:00:00') as hour
,minute('2021-12-01 10:00:00') as minute
,second('2021-12-01 10:00:00') as second
,weekofyear('2021-12-01 10:00:00') as weekofyear
10、转成日期
select to_date('2021-12-01 10:00:00') ;
11、当月最后一天
select last_day('2021-12-01 10:03:01');
12、当月第一天
select trunc(current_date,'MM') as day;
13、当年第一天
select trunc(current_date,'YY') as day;
14、next_day，返回当前时间的下一个星期几所对应的日期
select next_day('2021-12-01 10:03:01', 'TU');
15、hive中怎么获取两个日期相减后的小时（精确到两位小数点），而且这两个日期有可能会出现一个日期有时分秒，一个日期没有时分秒的情况
-- hive中怎么获取两个日期相减后的小时（精确到两位小数点），而且这两个日期有可能会出现一个日期有时分秒，一个日期没有时分秒的情况
select
t3.day1
,t3.day2
,t3.day -- 日期
,t3.hour -- 小时
,t3.min -- 分钟
,t3.day + t3.hour as hour_diff_1
,t3.day + t3.hour + t3.min as hour_diff_2
,round((cast(cast(t3.day1 as timestamp) as bigint) - cast(cast(t3.day2 as timestamp) as bigint)) / 3600,2) as hour_diff_3 -- 最优
,(datediff(t3.day1,t3.day2) * 24) + (nvl(hour(t3.day1),0) - nvl(hour(t3.day2),0)) + round((nvl(minute(t3.day1),0) - nvl(minute(t3.day2),0)) / 60,2) as hour_diff_4
from (
select
t2.day1
,t2.day2
,(datediff(t2.day1,t2.day2) * 24) as day -- 日期
,(hour(t2.day1) - hour(t2.day2)) as hour -- 小时
,round((minute(t2.day1) - minute(t2.day2)) / 60,2) as min -- 分钟
from (
select
cast(t1.day1 as timestamp) as day1
,cast(t1.day2 as timestamp) as day2
from (
select '2018-01-03 02:30:00' as day1, '2018-01-02 23:00:00' as day2 union all
select '2018-06-02 08:15:22' as day1, '2018-06-02 06:11:16' as day2 union all
select '2018-07-04' as day1, '2018-07-02 01:01:01' as day2
) t1
) t2
) t3
;
+------------------------+------------------------+------+-------+--------+--------------+--------------+--------------+--------------+--+
| day1 | day2 | day | hour | min | hour_diff_1 | hour_diff_2 | hour_diff_3 | hour_diff_4 |
+------------------------+------------------------+------+-------+--------+--------------+--------------+--------------+--------------+--+
| 2018-07-04 00:00:00.0 | 2018-07-02 01:01:01.0 | 48 | -1 | -0.02 | 47 | 46.98 | 46.98 | 46.98 |
| 2018-01-03 02:30:00.0 | 2018-01-02 23:00:00.0 | 24 | -21 | 0.5 | 3 | 3.5 | 3.5 | 3.5 |
| 2018-06-02 08:15:22.0 | 2018-06-02 06:11:16.0 | 0 | 2 | 0.07 | 2 | 2.07 | 2.07 | 2.07 |
+------------------------+------------------------+------+-------+--------+--------------+--------------+--------------+--------------+--+