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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） ADD_MONTHS

ADD_MONTHS

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计算日期值增加指定月数后的日期。此函数为MaxCompute 2.0扩展函数。

命令格式

string add_months(date|datetime|timestamp|string <startdate>, int <num_months>)

参数说明

  • startdate：必填。DATE、DATETIME、TIMESTAMP或STRING类型，格式为yyyy-mm-dd、yyyy-mm-dd hh:mi:ss或yyyy-mm-dd hh:mi:ss.ff3。取值为STRING类型格式时，至少要包含yyyy-mm-dd且不含多余的字符串。

  • num_months：必填。INT型数值。

返回值说明

返回开始日期startdate增加num_months个月后的日期，返回STRING类型的日期值，格式为yyyy-mm-dd。返回规则如下：

  • startdate非DATE、DATETIME、TIMESTAMP或STRING类型，或格式不符合要求时，返回NULL。

  • startdate值为NULL时，返回报错。

  • num_months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 00:00:00.123456789 | 2021-10-29 | 2021-10-29 00:00:00 | 2021-10-11 00:00:00.123456789 | 2021-11-20 | 123456780  |
| 2    | 2021-11-28 | 2021-11-28 00:02:00 | 2021-02-11 00:00:00.123456789 | 2021-10-29 | 2021-10-29 00:00:00 | 2021-10-11 00:00:00.123456789 | 2021-11-21 | 123456781  |
| 3    | 2021-11-27 | 2021-11-27 00:03:00 | 2021-03-11 00:00:00.123456789 | 2021-10-29 | 2021-10-29 00:00:00 | 2021-10-11 00:00:00.123456789 | 2021-11-22 | 123456782  |
| 4    | 2021-11-26 | 2021-11-26 00:04:00 | 2021-04-11 00:00:00.123456789 | 2021-10-29 | 2021-10-29 00:00:00 | 2021-10-11 00:00:00.123456789 | 2021-11-23 | 123456783  |
| 5    | 2021-11-25 | 2021-11-25 00:05:00 | 2021-05-11 00:00:00.123456789 | 2021-10-29 | 2021-10-29 00:00:00 | 2021-10-11 00:00:00.123456789 | 2021-11-24 | 123456784  |
| 6    | 2021-11-24 | 2021-11-24 00:06:00 | 2021-06-11 00:00:00.123456789 | 2021-10-29 | 2021-10-29 00:00:00 | 2021-10-11 00:00:00.123456789 | 2021-11-25 | 123456785  |
| 7    | 2021-11-23 | 2021-11-23 00:07:00 | 2021-07-11 00:00:00.123456789 | 2021-10-29 | 2021-10-29 00:00:00 | 2021-10-11 00:00:00.123456789 | 2021-11-26 | 123456786  |
| 8    | 2021-11-22 | 2021-11-22 00:08:00 | 2021-08-11 00:00:00.123456789 | 2021-10-29 | 2021-10-29 00:00:00 | 2021-10-11 00:00:00.123456789 | 2021-11-27 | 123456787  |
| 9    | 2021-11-21 | 2021-11-21 00:09:00 | 2021-09-11 00:00:00.123456789 | 2021-10-29 | 2021-10-29 00:00:00 | 2021-10-11 00:00:00.123456789 | 2021-11-28 | 123456788  |
| 10   | 2021-11-20 | 2021-11-20 00:10:00 | 2021-10-11 00:00:00.123456789 | 2021-10-29 | 2021-10-29 00:00:00 | 2021-10-11 00:00:00.123456789 | 2021-11-29 | 123456789  |
+------+-------+------------+------------+-------+------------+------------+-------+------------+

使用示例：静态数据示例

--返回2017-05-14。
select add_months('2017-02-14',3);
--返回2017-05-14。
select add_months('2017-2-14',3);
--返回2017-05-14。
select add_months('2017-02-14 21:30:00',3);
--返回NULL。
select add_months('20170214',3);
--返回NULL。
select add_months('2017-02-14 21:30:00',null);

使用示例：表数据示例

基于示例数据，将date1、datetime1、timestamp1和date3列日期转换为整型的UNIX格式的日期值，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, add_months(date1,1) as date1_add_months, datetime1, add_months(datetime1, 2) as datetime1_add_months, timestamp1, add_months(timestamp1,3) as timestamp1_add_months, date3, add_months(date3,4) as date3_add_months from mf_date_fun_t;

返回结果如下。

+------------+------------------+---------------------+----------------------+-------------------------------+-----------------------+------------+------------------+
| date1      | date1_add_months | datetime1           | datetime1_add_months | timestamp1                    | timestamp1_add_months | date3      | date3_add_months |
+------------+------------------+---------------------+----------------------+-------------------------------+-----------------------+------------+------------------+
| 2021-11-29 | 2021-12-29       | 2021-11-29 00:01:00 | 2022-01-29           | 2021-01-11 00:00:00.123456789 | 2021-04-11            | 2021-11-20 | 2022-03-20       |
| 2021-11-28 | 2021-12-28       | 2021-11-28 00:02:00 | 2022-01-28           | 2021-02-11 00:00:00.123456789 | 2021-05-11            | 2021-11-21 | 2022-03-21       |
| 2021-11-27 | 2021-12-27       | 2021-11-27 00:03:00 | 2022-01-27           | 2021-03-11 00:00:00.123456789 | 2021-06-11            | 2021-11-22 | 2022-03-22       |
| 2021-11-26 | 2021-12-26       | 2021-11-26 00:04:00 | 2022-01-26           | 2021-04-11 00:00:00.123456789 | 2021-07-11            | 2021-11-23 | 2022-03-23       |
| 2021-11-25 | 2021-12-25       | 2021-11-25 00:05:00 | 2022-01-25           | 2021-05-11 00:00:00.123456789 | 2021-08-11            | 2021-11-24 | 2022-03-24       |
| 2021-11-24 | 2021-12-24       | 2021-11-24 00:06:00 | 2022-01-24           | 2021-06-11 00:00:00.123456789 | 2021-09-11            | 2021-11-25 | 2022-03-25       |
| 2021-11-23 | 2021-12-23       | 2021-11-23 00:07:00 | 2022-01-23           | 2021-07-11 00:00:00.123456789 | 2021-10-11            | 2021-11-26 | 2022-03-26       |
| 2021-11-22 | 2021-12-22       | 2021-11-22 00:08:00 | 2022-01-22           | 2021-08-11 00:00:00.123456789 | 2021-11-11            | 2021-11-27 | 2022-03-27       |
| 2021-11-21 | 2021-12-21       | 2021-11-21 00:09:00 | 2022-01-21           | 2021-09-11 00:00:00.123456789 | 2021-12-11            | 2021-11-28 | 2022-03-28       |
| 2021-11-20 | 2021-12-20       | 2021-11-20 00:10:00 | 2022-01-20           | 2021-10-11 00:00:00.123456789 | 2022-01-11            | 2021-11-29 | 2022-03-29       |
+------------+------------------+---------------------+----------------------+-------------------------------+-----------------------+------------+------------------+

相关函数

ADD_MONTHS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。

上一篇：ACOS下一篇：ADD_KEY_TO_KEYSET
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