【Hive】日期函数

Hive版本: hive-1.1.0-cdh5.14.2

1. Unix时间戳转日期：from_unixtime

语法：from_unixtime(bigint unixtime[, string format])
返回值：string
描述: Unix时间戳转换为日期格式

0: jdbc:hive2://node03:10000> select from_unixtime(1237573801, 'yyyy-MM-dd HH:mm:ss') as time_string;
+----------------------+--+
|     time_string      |
+----------------------+--+
| 2009-03-21 02:30:01  |
+----------------------+--+
1 row selected (0.14 seconds)
0: jdbc:hive2://node03:10000> select from_unixtime(1237573801) as time;
+----------------------+--+
|         time         |
+----------------------+--+
| 2009-03-21 02:30:01  |
+----------------------+--+
1 row selected (0.126 seconds)

2. 当前Unix时间戳：unix_timestamp

语法：unix_timestamp()
返回值: bigint
描述：返回当前时间的Unix时间戳

0: jdbc:hive2://node03:10000> select unix_timestamp() as current_time;
+---------------+--+
| current_time  |
+---------------+--+
| 1592639728    |
+---------------+--+

3. 日期转Unix时间戳：unix_timestamp

语法: unix_timestamp(string date)
返回值: bigint
描述：返回指定日期的Unix时间戳

0: jdbc:hive2://node03:10000> select unix_timestamp('2009-03-20 11:30:01') as time_in_seconds;
+------------------+--+
| time_in_seconds  |
+------------------+--+
| 1237519801       |
+------------------+--+
1 row selected (0.138 seconds)

4. 指定日期某部分转为Unix时间戳：unix_timestamp

语法：unix_timestamp(string date, string pattern)
返回值: bigint
描述：根据指定的pattern，转换日期为Unix时间戳

0: jdbc:hive2://node03:10000> select unix_timestamp('2009-03-20', 'yyyy-MM-dd') as time_in_seconds;
+------------------+--+
| time_in_seconds  |
+------------------+--+
| 1237478400       |
+------------------+--+
1 row selected (0.121 seconds)

5. 时间戳转日期：to_date

语法：to_date(string timestamp)
返回值: 2.1.0版本前返回string，2.1.0版本后返回date
描述: 把指定的时间戳转换为日期格式

0: jdbc:hive2://node03:10000> select to_date("1970-01-01 00:00:00") as date1;
+-------------+--+
|    date1    |
+-------------+--+
| 1970-01-01  |
+-------------+--+
1 row selected (0.141 seconds)

6. 提取日期中的年份：year

语法：year(string date)
返回值：int
描述：提取日期中的年份部分

0: jdbc:hive2://node03:10000> select year('2020-06-20 16:01:00') as year;
+-------+--+
| year  |
+-------+--+
| 2020  |
+-------+--+
1 row selected (0.116 seconds)
0: jdbc:hive2://node03:10000> select year('2020-06-20') as year;
+-------+--+
| year  |
+-------+--+
| 2020  |
+-------+--+
1 row selected (0.119 seconds)

7. 提取日期中的月份：month

语法：month(string date)
返回值: int
描述：提取日期中的月份部分

0: jdbc:hive2://node03:10000> select month('2020-06-20') as month;
+--------+--+
| month  |
+--------+--+
| 6      |
+--------+--+
1 row selected (0.127 seconds)
0: jdbc:hive2://node03:10000> select month('2020-06-20 16:08:00') as month;
+--------+--+
| month  |
+--------+--+
| 6      |
+--------+--+
1 row selected (0.112 seconds)

8. 提取日期中的日：day

语法: day(string date) 、dayofmonth(date)
返回值: int
描述：提取日期中的日部分

0: jdbc:hive2://node03:10000> select day('2020-06-20') as day;
+------+--+
| day  |
+------+--+
| 20   |
+------+--+
1 row selected (0.189 seconds)
0: jdbc:hive2://node03:10000> select dayofmonth('2020-06-20') as day;
+------+--+
| day  |
+------+--+
| 20   |
+------+--+
1 row selected (0.106 seconds)

9. 提取日期中的小时：hour

语法：hour(string date)
返回值：int
描述：提取日期中的小时部分

0: jdbc:hive2://node03:10000> select hour('2020-06-20 16:08:00') as hour;
+-------+--+
| hour  |
+-------+--+
| 16    |
+-------+--+
1 row selected (0.113 seconds)
0: jdbc:hive2://node03:10000> select hour('16:08:00') as hour;
+-------+--+
| hour  |
+-------+--+
| 16    |
+-------+--+

10. 提取日期中的分钟/秒：minute/second

语法：minute(string date) / second(string date)
返回值: int
描述：提取日期中的分钟/秒部分

0: jdbc:hive2://node03:10000> select hour('2020-06-20 16:08:00') as hour,
. . . . . . . . . . . . . . > minute('2020-06-20 16:08:00') as monute,
. . . . . . . . . . . . . . > second('2020-06-20 16:08:00') as second
. . . . . . . . . . . . . . > ;
+-------+---------+---------+--+
| hour  | monute  | second  |
+-------+---------+---------+--+
| 16    | 8       | 0       |
+-------+---------+---------+--+

11. 返回日期处于当年的第几周：weekofyear

语法：weekofyear(string date)
返回值：int
描述: 返回指定日期处于当年的第几周

0: jdbc:hive2://node03:10000> select weekofyear('2020-06-20') as weekofyear;
+-------------+--+
| weekofyear  |
+-------------+--+
| 25          |
+-------------+--+
1 row selected (0.139 seconds)

12. 两日期间隔天数：datediff

语法：datediff(string enddate, string startdate)
返回值: int
描述: 返回两指定日期之间的天数

0: jdbc:hive2://node03:10000> select datediff('2020-06-20', '2020-06-15') as days;
+-------+--+
| days  |
+-------+--+
| 5     |
+-------+--+
1 row selected (0.138 seconds)

13. 日期增加函数: dateadd

语法：date_add(date/timestamp/string startdate, tinyint/smallint/int days)
返回值: 2.1.0版本前返回string，2.1.0版本后返回date
描述：返回开始日期startdate增加天数days后的日期

0: jdbc:hive2://node03:10000> select date_add('2020-06-15', 5) as date;
+-------------+--+
|    date     |
+-------------+--+
| 2020-06-20  |
+-------------+--+
1 row selected (0.14 seconds)

14. 日期减少函数: datesub

语法: date_sub(date/timestamp/string startdate, tinyint/smallint/int days)
返回值: 2.1.0版本前返回string，2.1.0版本后返回date
描述: 返回开始日期startdate减少天数days后的日期

0: jdbc:hive2://node03:10000> select date_sub('2020-06-20', 5) as date;
+-------------+--+
|    date     |
+-------------+--+
| 2020-06-15  |
+-------------+--+
1 row selected (0.128 seconds)

15. 当前日期/当前时间戳：current_date / current_timestamp

语法: current_date / current_timestamp
返回值：date / timestamp
描述: 返回当前日期或者时间戳

0: jdbc:hive2://node03:10000> select current_date as date, current_timestamp as timestamp;
+-------------+--------------------------+--+
|    date     |        timestamp         |
+-------------+--------------------------+--+
| 2020-06-20  | 2020-06-20 18:19:35.736  |
+-------------+--------------------------+--+
1 row selected (0.145 seconds)

16. 月份增加函数：add_months

语法: add_months(string start_date, int num_months, output_date_format)
返回值: string
描述: 返回开始日期start_date增加num_months月后的日期，output_date_format做为可选参数只在Hive 4.0.0版本后可用。

0: jdbc:hive2://node03:10000> select add_months('2020-06-30', 1) as add_months;
+-------------+--+
| add_months  |
+-------------+--+
| 2020-07-31  |
+-------------+--+
1 row selected (0.138 seconds)

17. 当月最后一天：last_day

语法：last_day(string date)
返回值: string
描述: 返回指定日期所在月份的最后一天

0: jdbc:hive2://node03:10000> select last_day(current_date) as last_day;
+-------------+--+
|  last_day   |
+-------------+--+
| 2020-06-30  |
+-------------+--+
1 row selected (0.117 seconds)
0: jdbc:hive2://node03:10000> select last_day(current_timestamp) as last_day;
+-------------+--+
|  last_day   |
+-------------+--+
| 2020-06-30  |
+-------------+--+
1 row selected (0.105 seconds)

18. 下一个周几的日期：next_day

语法: next_day(string start_date, string day_of_week)
返回值: string
描述: 返回开始日期start_date后的第一个周几(如周一)的日期，其中day_of_week可以为星期的2或3位缩写如：Mo, tue，也可以是星期的全拼，如：FRIDAY

0: jdbc:hive2://node03:10000>  select next_day('2020-06-20', 'MON') as next_monday;
+--------------+--+
| next_monday  |
+--------------+--+
| 2020-06-22   |
+--------------+--+
1 row selected (0.16 seconds)

19. 截断日期：trunc

语法：trunc(string date, string format)
返回值: string
描述：按指定格式截断日期，format可以为月或年：MONTH/MON/MM, YEAR/YYYY/YY

0: jdbc:hive2://node03:10000> select trunc('2020-06-20', 'MM') as trunc_mon;
+-------------+--+
|  trunc_mon  |
+-------------+--+
| 2020-06-01  |
+-------------+--+
1 row selected (0.133 seconds)
0: jdbc:hive2://node03:10000> select trunc('2020-06-20', 'YEAR') as trunc_date;
+-------------+--+
| trunc_date  |
+-------------+--+
| 2020-01-01  |
+-------------+--+
1 row selected (0.164 seconds)

20. 计算间隔月份：months_between

语法：months_between(date1, date2)
返回值: double
描述: 返回两日期的间隔月份，精度到小数点后最多8位

0: jdbc:hive2://node03:10000> select months_between('2020-06-20','2020-06-01') as months_between1,
. . . . . . . . . . . . . . > months_between('2020-06-20','2020-06-20') as months_between2,
. . . . . . . . . . . . . . > months_between('2020-06-20','2020-05-20') as months_between3,
. . . . . . . . . . . . . . > months_between('2020-06-20','2020-07-20') as months_between4;
+------------------+------------------+------------------+------------------+--+
| months_between1  | months_between2  | months_between3  | months_between4  |
+------------------+------------------+------------------+------------------+--+
| 0.61290323       | 0.0              | 1.0              | -1.0             |
+------------------+------------------+------------------+------------------+--+
1 row selected (0.127 seconds)