---
{
    "title": "time_round",
    "language": "zh-CN"
}
---

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# time_round
## description
### Syntax

`DATETIME TIME_ROUND(DATETIME expr)`

`DATETIME TIME_ROUND(DATETIME expr, INT period)`

`DATETIME TIME_ROUND(DATETIME expr, DATETIME origin)`

`DATETIME TIME_ROUND(DATETIME expr, INT period, DATETIME origin)`

函数名 `TIME_ROUND` 由两部分组成，每部分由以下可选值组成
- `TIME`: `SECOND`, `MINUTE`, `HOUR`, `DAY`, `WEEK`, `MONTH`, `YEAR`
- `ROUND`: `FLOOR`, `CEIL`

返回 `expr` 的上/下界。

- `period` 指定每个周期有多少个 `TIME` 单位组成，默认为 `1`。
- `origin` 指定周期的开始时间，默认为 `1970-01-01T00:00:00`，`WEEK` 的默认开始时间为 `1970-01-04T00:00:00`，即周日。可以比 `expr` 大。
- 请尽量选择常见 `period`，如 3 `MONTH`，90 `MINUTE` 等，如设置了非常用 `period`，请同时指定 `origin`。

## example

```

MySQL> SELECT YEAR_FLOOR('20200202000000');
+------------------------------+
| year_floor('20200202000000') |
+------------------------------+
| 2020-01-01 00:00:00          |
+------------------------------+


MySQL> SELECT MONTH_CEIL(CAST('2020-02-02 13:09:20' AS DATETIME), 3); --quarter
+--------------------------------------------------------+
| month_ceil(CAST('2020-02-02 13:09:20' AS DATETIME), 3) |
+--------------------------------------------------------+
| 2020-04-01 00:00:00                                    |
+--------------------------------------------------------+


MySQL> SELECT WEEK_CEIL('2020-02-02 13:09:20', '2020-01-06'); --monday
+---------------------------------------------------------+
| week_ceil('2020-02-02 13:09:20', '2020-01-06 00:00:00') |
+---------------------------------------------------------+
| 2020-02-03 00:00:00                                     |
+---------------------------------------------------------+


MySQL> SELECT MONTH_CEIL(CAST('2020-02-02 13:09:20' AS DATETIME), 3, CAST('1970-01-09 00:00:00' AS DATETIME)); --next rent day
+-------------------------------------------------------------------------------------------------+
| month_ceil(CAST('2020-02-02 13:09:20' AS DATETIME), 3, CAST('1970-01-09 00:00:00' AS DATETIME)) |
+-------------------------------------------------------------------------------------------------+
| 2020-04-09 00:00:00                                                                             |
+-------------------------------------------------------------------------------------------------+

```
## keyword
TIME_ROUND