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首页 云原生大数据计算服务 MaxCompute 操作指南 开发参考：SQL 函数参考 内建函数（字母排序） DATEPART

DATEPART

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提取日期date中符合指定时间单位datepart的值。

命令格式

bigint datepart(date|datetime|timestamp <date>, string <datepart>)

参数说明

  • date：必填。DATE、DATETIME或TIMESTAMP类型。如果输入为STRING类型，且MaxCompute项目的数据类型版本是1.0，则会隐式转换为DATETIME类型后参与运算。

  • datepart：必填。STRING类型常量，支持扩展的日期格式。

    此字段的取值遵循STRING与DATETIME类型转换的约定，即yyyy表示年，mm表示月，dd表示天。关于类型转换的规则，详情请参见数据类型转换。该字段也支持扩展的日期格式：年-year、月-month或-mon、日-day和小时-hour。

返回值说明

返回BIGINT类型。返回规则如下：

  • date非DATE、DATETIME或TIMESTAMP类型时，返回报错。

  • date值为NULL时，返回报错。

  • datepart值为NULL时，返回NULL。

示例数据

为便于理解各函数的使用方法，本文为您提供源数据，基于源数据提供函数相关示例。创建表mf_date_fun_t，并添加数据，命令示例如下。

create table if not exists mf_date_fun_t(
    id      int,
    date1   date,
    datetime1   datetime,
    timestamp1 timestamp,
    date2   date,
    datetime2   datetime,
    timestamp2 timestamp,
    date3 string,
    date4 bigint);
insert into mf_date_fun_t values
(1,DATE'2021-11-29',DATETIME'2021-11-29 00:01:00',TIMESTAMP'2021-01-11 00:00:00.123456789',DATE'2021-10-29',DATETIME'2021-10-29 00:00:00',TIMESTAMP'2021-10-11 00:00:00.123456789','2021-11-20',123456780),
(2,DATE'2021-11-28',DATETIME'2021-11-28 00:02:00',TIMESTAMP'2021-02-11 00:00:00.123456789',DATE'2021-10-29',DATETIME'2021-10-29 00:00:00',TIMESTAMP'2021-10-11 00:00:00.123456789','2021-11-21',123456781),
(3,DATE'2021-11-27',DATETIME'2021-11-27 00:03:00',TIMESTAMP'2021-03-11 00:00:00.123456789',DATE'2021-10-29',DATETIME'2021-10-29 00:00:00',TIMESTAMP'2021-10-11 00:00:00.123456789','2021-11-22',123456782),
(4,DATE'2021-11-26',DATETIME'2021-11-26 00:04:00',TIMESTAMP'2021-04-11 00:00:00.123456789',DATE'2021-10-29',DATETIME'2021-10-29 00:00:00',TIMESTAMP'2021-10-11 00:00:00.123456789','2021-11-23',123456783),
(5,DATE'2021-11-25',DATETIME'2021-11-25 00:05:00',TIMESTAMP'2021-05-11 00:00:00.123456789',DATE'2021-10-29',DATETIME'2021-10-29 00:00:00',TIMESTAMP'2021-10-11 00:00:00.123456789','2021-11-24',123456784),
(6,DATE'2021-11-24',DATETIME'2021-11-24 00:06:00',TIMESTAMP'2021-06-11 00:00:00.123456789',DATE'2021-10-29',DATETIME'2021-10-29 00:00:00',TIMESTAMP'2021-10-11 00:00:00.123456789','2021-11-25',123456785),
(7,DATE'2021-11-23',DATETIME'2021-11-23 00:07:00',TIMESTAMP'2021-07-11 00:00:00.123456789',DATE'2021-10-29',DATETIME'2021-10-29 00:00:00',TIMESTAMP'2021-10-11 00:00:00.123456789','2021-11-26',123456786),
(8,DATE'2021-11-22',DATETIME'2021-11-22 00:08:00',TIMESTAMP'2021-08-11 00:00:00.123456789',DATE'2021-10-29',DATETIME'2021-10-29 00:00:00',TIMESTAMP'2021-10-11 00:00:00.123456789','2021-11-27',123456787),
(9,DATE'2021-11-21',DATETIME'2021-11-21 00:09:00',TIMESTAMP'2021-09-11 00:00:00.123456789',DATE'2021-10-29',DATETIME'2021-10-29 00:00:00',TIMESTAMP'2021-10-11 00:00:00.123456789','2021-11-28',123456788),
(10,DATE'2021-11-20',DATETIME'2021-11-20 00:10:00',TIMESTAMP'2021-10-11 00:00:00.123456789',DATE'2021-10-29',DATETIME'2021-10-29 00:00:00',TIMESTAMP'2021-10-11 00:00:00.123456789','2021-11-29',123456789);

查询表mf_date_fun_t中的数据，命令示例如下：

select * from mf_date_fun_t;
--返回结果。
+------------+------------+---------------------+-------------------------+------------+---------------------+-------------------------+------------+------------+
| id         | date1      | datetime1           | timestamp1              | date2      | datetime2           | timestamp2              | date3      | date4      |
+------------+------------+---------------------+-------------------------+------------+---------------------+-------------------------+------------+------------+
| 1          | 2021-11-29 | 2021-11-29 00:01:00 | 2021-01-11 00:00:00.123 | 2021-10-29 | 2021-10-29 00:00:00 | 2021-10-11 00:00:00.123 | 2021-11-20 | 123456780  |
| 2          | 2021-11-28 | 2021-11-28 00:02:00 | 2021-02-11 00:00:00.123 | 2021-10-29 | 2021-10-29 00:00:00 | 2021-10-11 00:00:00.123 | 2021-11-21 | 123456781  |
| 3          | 2021-11-27 | 2021-11-27 00:03:00 | 2021-03-11 00:00:00.123 | 2021-10-29 | 2021-10-29 00:00:00 | 2021-10-11 00:00:00.123 | 2021-11-22 | 123456782  |
| 4          | 2021-11-26 | 2021-11-26 00:04:00 | 2021-04-11 00:00:00.123 | 2021-10-29 | 2021-10-29 00:00:00 | 2021-10-11 00:00:00.123 | 2021-11-23 | 123456783  |
| 5          | 2021-11-25 | 2021-11-25 00:05:00 | 2021-05-11 00:00:00.123 | 2021-10-29 | 2021-10-29 00:00:00 | 2021-10-11 00:00:00.123 | 2021-11-24 | 123456784  |
| 6          | 2021-11-24 | 2021-11-24 00:06:00 | 2021-06-11 00:00:00.123 | 2021-10-29 | 2021-10-29 00:00:00 | 2021-10-11 00:00:00.123 | 2021-11-25 | 123456785  |
| 7          | 2021-11-23 | 2021-11-23 00:07:00 | 2021-07-11 00:00:00.123 | 2021-10-29 | 2021-10-29 00:00:00 | 2021-10-11 00:00:00.123 | 2021-11-26 | 123456786  |
| 8          | 2021-11-22 | 2021-11-22 00:08:00 | 2021-08-11 00:00:00.123 | 2021-10-29 | 2021-10-29 00:00:00 | 2021-10-11 00:00:00.123 | 2021-11-27 | 123456787  |
| 9          | 2021-11-21 | 2021-11-21 00:09:00 | 2021-09-11 00:00:00.123 | 2021-10-29 | 2021-10-29 00:00:00 | 2021-10-11 00:00:00.123 | 2021-11-28 | 123456788  |
| 10         | 2021-11-20 | 2021-11-20 00:10:00 | 2021-10-11 00:00:00.123 | 2021-10-29 | 2021-10-29 00:00:00 | 2021-10-11 00:00:00.123 | 2021-11-29 | 123456789  |
+------------+------------+---------------------+-------------------------+------------+---------------------+-------------------------+------------+------------+

使用示例：静态数据示例

--返回2013。
select datepart(datetime'2013-06-08 01:10:00', 'yyyy'); 
--返回6。
select datepart(datetime'2013-06-08 01:10:00', 'mm');
--返回2013。
select datepart(date '2013-06-08', 'yyyy');
--开启2.0新类型。此命令需要与SQL语句一起提交。返回2013。
set odps.sql.type.system.odps2=true;
select datepart(timestamp '2013-06-08 01:10:00', 'yyyy');
--返回2013。
set odps.sql.type.system.odps2=false;
select datepart('2013-06-08 01:10:00', 'yyyy');
--返回NULL。
select datepart(date '2013-06-08', null);

使用示例：表数据示例

基于示例数据，提取date1、datetime1和timestamp1中符合指定时间单位的值，命令示例如下。

--开启2.0新类型。此命令需要与SQL语句一起提交。
set odps.sql.type.system.odps2=true;
select date1, datepart(date1,'yyyy') as date1_datepart, datetime1, datepart(datetime1,'dd') as datetime1_datepart, timestamp1, datepart(timestamp1,'mm') as timestamp1_datepart from mf_date_fun_t;

返回结果如下。

+------------+----------------+---------------------+-------------------------+-------------------------------+---------------------+
| date1      | date1_datepart | datetime1           | datetime1_datepart      | timestamp1                    | timestamp1_datepart |
+------------+----------------+---------------------+-------------------------+-------------------------------+---------------------+
| 2021-11-29 | 2021           | 2021-11-29 00:01:00 | 29                      | 2021-01-11 00:00:00.123456789 | 1                   |
| 2021-11-28 | 2021           | 2021-11-28 00:02:00 | 28                      | 2021-02-11 00:00:00.123456789 | 2                   |
| 2021-11-27 | 2021           | 2021-11-27 00:03:00 | 27                      | 2021-03-11 00:00:00.123456789 | 3                   |
| 2021-11-26 | 2021           | 2021-11-26 00:04:00 | 26                      | 2021-04-11 00:00:00.123456789 | 4                   |
| 2021-11-25 | 2021           | 2021-11-25 00:05:00 | 25                      | 2021-05-11 00:00:00.123456789 | 5                   |
| 2021-11-24 | 2021           | 2021-11-24 00:06:00 | 24                      | 2021-06-11 00:00:00.123456789 | 6                   |
| 2021-11-23 | 2021           | 2021-11-23 00:07:00 | 23                      | 2021-07-11 00:00:00.123456789 | 7                   |
| 2021-11-22 | 2021           | 2021-11-22 00:08:00 | 22                      | 2021-08-11 00:00:00.123456789 | 8                   |
| 2021-11-21 | 2021           | 2021-11-21 00:09:00 | 21                      | 2021-09-11 00:00:00.123456789 | 9                   |
| 2021-11-20 | 2021           | 2021-11-20 00:10:00 | 20                      | 2021-10-11 00:00:00.123456789 | 10                  |
+------------+----------------+---------------------+-------------------------+-------------------------------+---------------------+

相关函数

DATEPART函数属于日期函数，更多日期计算、日期转换的相关函数请参见日期函数。

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