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(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 ,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 \'2018-01-02 01:01:01\' as day union all select \'2018-02-02 02:03:04\' as day union all select \'2018-03-02 03:05:07\' as day union all select \'2018-04-02 04:07:10\' as day union all select \'2018-05-02 05:09:13\' as day union all select \'2018-06-02 06:11:16\' as day union all select \'2018-07-02 07:13:19\' as day union all select \'2018-08-02 08:15:22\' as day union all select \'2018-09-02 09:17:25\' as day union all select \'2018-10-02 10:19:28\' as day union all select \'2018-11-02 11:21:31\' as day union all select \'2018-12-02 12:23:34\' as day ) t1 ;
获取当前时间截:
1 select unix_timestamp() ; 2 +-------------+--+ 3 | _c0 | 4 +-------------+--+ 5 | 1521684090 | 6 +-------------+--+
获取当前时间1：
1 select current_timestamp; 2 +--------------------------+--+ 3 | _c0 | 4 +--------------------------+--+ 5 | 2018-03-22 10:04:02.568 | 6 +--------------------------+--+
获取当前时间2：
1 SELECT from_unixtime(unix_timestamp()); 2 +----------------------+--+ 3 | _c0 | 4 +----------------------+--+ 5 | 2018-03-22 10:04:38 | 6 +----------------------+--+
获取当前日期：
1 SELECT CURRENT_DATE; 2 +-------------+--+ 3 | _c0 | 4 +-------------+--+ 5 | 2018-03-22 | 6 +-------------+--+
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。
1 select datediff(CURRENT_DATE,\'2017-01-01\') as datediff; 2 +-----------+--+ 3 | datediff | 4 +-----------+--+ 5 | 445 | 6 +-----------+--+
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。
1 select date_add(current_date,365) as dateadd; 2 +-------------+--+ 3 | dateadd | 4 +-------------+--+ 5 | 2019-03-22 | 6 +-------------+--+
时间差：两个日期之间的小时差
1 select (hour(\'2018-02-27 10:00:00\')-hour(\'2018-02-25 12:00:00\')+(datediff(\'2018-02-27 10:00:00\',\'2018-02-25 12:00:00\'))*24) as hour_subValue; 2 +----------------+--+ 3 | hour_subValue | 4 +----------------+--+ 5 | 46 | 6 +----------------+--+
获取年、月、日、小时、分钟、秒、当年第几周
1 select 2 year(\'2018-02-27 10:00:00\') as year 3 ,month(\'2018-02-27 10:00:00\') as month 4 ,day(\'2018-02-27 10:00:00\') as day 5 ,hour(\'2018-02-27 10:00:00\') as hour 6 ,minute(\'2018-02-27 10:00:00\') as minute 7 ,second(\'2018-02-27 10:00:00\') as second 8 ,weekofyear(\'2018-02-27 10:00:00\') as weekofyear 9 ; 10 +-------+--------+------+-------+---------+---------+-------------+--+ 11 | year | month | day | hour | minute | second | weekofyear | 12 +-------+--------+------+-------+---------+---------+-------------+--+ 13 | 2018 | 2 | 27 | 10 | 0 | 0 | 9 | 14 +-------+--------+------+-------+---------+---------+-------------+--+
转成日期：
1 select to_date(\'2018-02-27 10:03:01\') ; 2 +-------------+--+ 3 | _c0 | 4 +-------------+--+ 5 | 2018-02-27 | 6 +-------------+--+
当月最后一天：
1 select last_day(\'2018-02-27 10:03:01\'); 2 +-------------+--+ 3 | _c0 | 4 +-------------+--+ 5 | 2018-02-28 | 6 +-------------+--+
当月第一天：
1 select trunc(current_date,\'MM\') as day; 2 +-------------+--+ 3 | day | 4 +-------------+--+ 5 | 2018-03-01 | 6 +-------------+--+
当年第一天：
1 select trunc(current_date,\'YY\') as day; 2 +-------------+--+ 3 | day | 4 +-------------+--+ 5 | 2018-01-01 | 6 +-------------+--+
next_day，返回当前时间的下一个星期几所对应的日期
1 select next_day(\'2018-02-27 10:03:01\', \'TU\'); 2 +-------------+--+ 3 | _c0 | 4 +-------------+--+ 5 | 2018-03-06 | 6 +-------------+--+
-- 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 | +------------------------+------------------------+------+-------+--------+--------------+--------------+--------------+--------------+--+
### 当周第一天，最后一天 date -d "2018-10-24 $(($(date -d 2018-10-24 +%u)-1)) days ago" +%Y-%m-%d date -d "2018-10-24 $((7-$(date -d 2018-10-24 +%u))) days" +%Y-%m-%d