date_floor
description
Syntax
DATETIME DATE_FLOOR(DATETIME datetime, INTERVAL period type)
将日期转化为指定的时间间隔周期的最近下取整时刻。
datetime 参数是合法的日期表达式。
period 参数是指定每个周期有多少个单位组成，开始的时间起点为0001-01-01T00:00:00.
type 参数可以是下列值：YEAR, MONTH, DAY, HOUR, MINUTE, SECOND.
example
mysql>select date_floor("0001-01-01 00:00:16",interval 5 second);
+---------------------------------------------------------------+
| second_floor('0001-01-01 00:00:16', 5, '0001-01-01 00:00:00') |
+---------------------------------------------------------------+
| 0001-01-01 00:00:15 |
+---------------------------------------------------------------+
1 row in set (0.00 sec)
mysql>select date_floor("0001-01-01 00:00:18",interval 5 second);
+---------------------------------------------------------------+
| second_floor('0001-01-01 00:00:18', 5, '0001-01-01 00:00:00') |
+---------------------------------------------------------------+
| 0001-01-01 00:00:15 |
+---------------------------------------------------------------+
1 row in set (0.01 sec)
mysql>select date_floor("2023-07-13 22:28:18",interval 5 minute);
+---------------------------------------------------------------+
| minute_floor('2023-07-13 22:28:18', 5, '0001-01-01 00:00:00') |
+---------------------------------------------------------------+
| 2023-07-13 22:25:00 |
+---------------------------------------------------------------+
1 row in set (0.00 sec)
mysql>select date_floor("2023-07-13 22:28:18",interval 5 hour);
+-------------------------------------------------------------+
| hour_floor('2023-07-13 22:28:18', 5, '0001-01-01 00:00:00') |
+-------------------------------------------------------------+
| 2023-07-13 18:00:00 |
+-------------------------------------------------------------+
1 row in set (0.01 sec)
mysql>select date_floor("2023-07-13 22:28:18",interval 5 day);
+------------------------------------------------------------+
| day_floor('2023-07-13 22:28:18', 5, '0001-01-01 00:00:00') |
+------------------------------------------------------------+
| 2023-07-10 00:00:00 |
+------------------------------------------------------------+
1 row in set (0.00 sec)
mysql>select date_floor("2023-07-13 22:28:18",interval 5 month);
+--------------------------------------------------------------+
| month_floor('2023-07-13 22:28:18', 5, '0001-01-01 00:00:00') |
+--------------------------------------------------------------+
| 2023-07-01 00:00:00 |
+--------------------------------------------------------------+
1 row in set (0.01 sec)
mysql>select date_floor("2023-07-13 22:28:18",interval 5 year);
+-------------------------------------------------------------+
| year_floor('2023-07-13 22:28:18', 5, '0001-01-01 00:00:00') |
+-------------------------------------------------------------+
| 2021-01-01 00:00:00 |
+-------------------------------------------------------------+
keywords
DATE_FLOOR,DATE,FLOORBest Practice
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