MySQL extract()函式 - tw511教學網

在本教學中，您將學習如何使用MySQL EXTRACT()函式來提取DATE或DATETIME值的一部分。

簡介MySQL EXTRACT函式

EXTRACT()函式提取日期的一部分。下面說明了EXTRACT()函式的語法。

EXTRACT(unit FROM date)

EXTRACT()函式需要兩個引數：unit和date。

unit是要從日期中提取的間隔。以下是unit引數的有效間隔。

DAY
DAY_HOUR
DAY_MICROSECOND
DAY_MINUTE
DAY_SECOND
HOUR
HOUR_MICROSECOND
HOUR_MINUTE
HOUR_SECOND
MICROSECOND
MINUTE
MINUTE_MICROSECOND
MINUTE_SECOND
MONTH
QUARTER
SECOND
SECOND_MICROSECOND
WEEK
YEAR
YEAR_MONTH

date是DATE或DATETIME值，從中提取間隔的日期。

MySQL EXTRACT函式範例

從日期時間提取日期：

mysql> SELECT EXTRACT(DAY FROM '2017-07-14 09:04:44') DAY;
+------+
| DAY  |
+------+
|   14 |
+------+
1 row in set (0.00 sec)

從datetime中提取day_hour：

mysql> SELECT EXTRACT(DAY_HOUR FROM '2017-07-14 09:04:44') DAYHOUR;
+---------+
| DAYHOUR |
+---------+
|    1409 |
+---------+
1 row in set (0.00 sec)

從datetime中提取day_microsecond：

mysql> SELECT EXTRACT(DAY_MICROSECOND FROM '2017-07-14 09:04:44') DAY_MS;
+----------------+
| DAY_MS         |
+----------------+
| 14090444000000 |
+----------------+
1 row in set (0.00 sec)

從datetime中提取day_minute：

mysql> SELECT EXTRACT(DAY_MINUTE FROM '2017-07-14 09:04:44') DAY_M;
+--------+
| DAY_M  |
+--------+
| 140904 |
+--------+
1 row in set (0.00 sec)

從datetime中提取day_second ：

mysql> SELECT EXTRACT(DAY_SECOND FROM '2017-07-14 09:04:44') DAY_S;
+----------+
| DAY_S    |
+----------+
| 14090444 |
+----------+
1 row in set (0.00 sec)

從datetime提取小時數：

mysql> SELECT EXTRACT(HOUR FROM '2017-07-14 09:04:44') HOUR;
+------+
| HOUR |
+------+
|    9 |
+------+
1 row in set (0.00 sec)

從datetime中提取hour_microsecond：

mysql> SELECT EXTRACT(HOUR_MICROSECOND FROM '2017-07-14 09:04:44') HOUR_MS;
+-------------+
| HOUR_MS     |
+-------------+
| 90444000000 |
+-------------+
1 row in set (0.00 sec)

從datetime中提取hour_minute：

mysql> SELECT EXTRACT(HOUR_MINUTE FROM '2017-07-14 09:04:44') HOUR_M;
+--------+
| HOUR_M |
+--------+
|    904 |
+--------+
1 row in set (0.00 sec)

從datetime中提取hour_second：

mysql> SELECT EXTRACT(HOUR_SECOND FROM '2017-07-14 09:04:44') HOUR_S;
+--------+
| HOUR_S |
+--------+
|  90444 |
+--------+
1 row in set (0.00 sec)

從datetime提取微秒：

mysql> SELECT EXTRACT(MICROSECOND FROM '2017-07-14 09:04:44') MICROSECOND;
+-------------+
| MICROSECOND |
+-------------+
|           0 |
+-------------+
1 row in set (0.00 sec)

從日期時間中提取分鐘：

mysql> SELECT EXTRACT(MINUTE FROM '2017-07-14 09:04:44') MINUTE;
+--------+
| MINUTE |
+--------+
|      4 |
+--------+
1 row in set (0.00 sec)

從datetime中提取minute_microsecond：

mysql> SELECT EXTRACT(MINUTE_MICROSECOND FROM '2017-07-14 09:04:44') MINUTE_MS;
+-----------+
| MINUTE_MS |
+-----------+
| 444000000 |
+-----------+
1 row in set (0.00 sec)

從datetime中提取minute_second：

mysql> SELECT EXTRACT(MINUTE_SECOND FROM '2017-07-14 09:04:44') MINUTE_S;
+----------+
| MINUTE_S |
+----------+
|      444 |
+----------+
1 row in set (0.00 sec)

從日期時間提取月份：

mysql> SELECT EXTRACT(MONTH FROM '2017-07-14 09:04:44') MONTH;
+-------+
| MONTH |
+-------+
|     7 |
+-------+
1 row in set (0.00 sec)

從日期時間提取季度：

mysql> SELECT EXTRACT(QUARTER FROM '2017-07-14 09:04:44') QUARTER;
+---------+
| QUARTER |
+---------+
|       3 |
+---------+
1 row in set (0.00 sec)

從datetime中提取秒數：

mysql> SELECT EXTRACT(SECOND FROM '2017-07-14 09:04:44') SECOND;
+--------+
| SECOND |
+--------+
|     44 |
+--------+
1 row in set (0.00 sec)

從datetime中提取second_microsecond：

mysql> SELECT EXTRACT(SECOND_MICROSECOND FROM '2017-07-14 09:04:44') SECOND_MS;
+-----------+
| SECOND_MS |
+-----------+
|  44000000 |
+-----------+
1 row in set (0.00 sec)

從datetime提取周：

mysql> SELECT EXTRACT(WEEK FROM '2017-07-14 09:04:44') WEEK;
+------+
| WEEK |
+------+
|   28 |
+------+
1 row in set (0.00 sec)

從日期時間提取年份：

mysql> SELECT EXTRACT(YEAR FROM '2017-07-14 09:04:44') YEAR;
+------+
| YEAR |
+------+
| 2017 |
+------+
1 row in set (0.00 sec)

從datetime提取year_month：

mysql> SELECT EXTRACT(YEAR_MONTH FROM '2017-07-14 09:04:44') YEARMONTH;
+-----------+
| YEARMONTH |
+-----------+
|    201707 |
+-----------+
1 row in set (0.00 sec)

在本教學中，您學習了如何使用MySQL EXTRACT()函式來提取DATE或DATETIME值的一部分。