EXTRACT（Lakehouse v1）

检索日期、时间或时间戳的指定部分。

另请参阅：DATE_PART

SQL 语法

EXTRACT( YEAR | QUARTER | MONTH | WEEK | DAY | HOUR | MINUTE | SECOND | DOW | DOY FROM <date_or_time_expr> )

• DOW：星期几。
• DOY：一年中的第几天。

返回类型

整数。

SQL 示例

SELECT NOW();

now()                |
---------------------+
2023-10-16 02:09:28.0|

SELECT EXTRACT(DAY FROM NOW());

extract(day from now())|
-----------------------+
                     16|

-- October 16, 2023, is a Monday
SELECT EXTRACT(DOW FROM NOW());

extract(dow from now())|
-----------------------+
                      1|

-- October 16, 2023, is the 289th day of the year
SELECT EXTRACT(DOY FROM NOW());

extract(doy from now())|
-----------------------+
                    289|

SELECT EXTRACT(MONTH FROM TO_DATE('2022-05-13'));

extract(month from to_date('2022-05-13'))|
-----------------------------------------+
                                        5|