# 日期和时间算术

__*DATE_ADD 函数*__
__*DATE_SUB 函数*__
__*INTERVAL 函数*__

+ `DATE_ADD, DATE_SUB`
+ `+/- INTERVAL`

```12
tidb> SELECT now() + interval '1 12:12:12.123456' ~!@DAY_MICROSECOND@!~,
    -> now() + interval '12.123456' ~!@SECOND_MICROSECOND@!~,
    -> now() - interval '1-3' ~!@YEAR_MONTH@!~,
    -> date_add(now(), interval 1 ~!@WEEK@!~),
    -> date_sub(now(), interval 1 ~!@QUARTER@!~)
    -> \G
*************************** 1. row ***************************
now() + interval '1 12:12:12.123456' DAY_MICROSECOND: 2022-01-07 22:29:02.123456
     now() + interval '12.123456' SECOND_MICROSECOND: 2022-01-06 10:17:02.123456
                   now() - interval '1-3' YEAR_MONTH: 2020-10-06 10:16:50
                    date_add(now(), interval 1 WEEK): 2022-01-13 10:16:50
                 date_sub(now(), interval 1 QUARTER): 2021-10-06 10:16:50
```
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DATE_ADD()	将时间间隔添加到日期上
DATE_SUB()	从日期减去指定的时间间隔