如何在 MySQL 中提取日期的年份和月份?
在 MySQL 中,可以通过以下三种方式实现
使用 EXTRACT() 函数
如果要同时提取年份和月份,可以使用 EXTRACT 函数。我们需要将 YEAR_MONTH 作为该函数的参数。为了理解这一点,请考虑以下使用“Collegedetail”表中的数据的函数:
mysql> Select EXTRACT(YEAR_MONTH From estb) from collegedetail; +-------------------------------+ | EXTRACT(YEAR_MONTH From estb) | +-------------------------------+ | 201005 | | 199510 | | 199409 | | 200107 | | 201007 | +-------------------------------+ 5 rows in set (0.00 sec)
使用 DATE_FORMAT() 函数
它可以同时或分别提取年份和月份。顾名思义,我们还可以格式化其输出。为了理解这一点,请考虑以下使用“Collegedetail”表中的数据的示例:
mysql> Select DATE_FORMAT(estb, '%Y %m') from collegedetail; +----------------------------+ | DATE_FORMAT(estb, '%Y %m') | +----------------------------+ | 2010 05 | | 1995 10 | | 1994 09 | | 2001 07 | | 2010 07 | +----------------------------+ 5 rows in set (0.00 sec) mysql> Select DATE_FORMAT(estb, '%Y') from Collegedetail; +-------------------------+ | DATE_FORMAT(estb, '%Y') | +-------------------------+ | 2010 | | 1995 | | 1994 | | 2001 | | 2010 | +-------------------------+ 5 rows in set (0.00 sec) mysql> Select DATE_FORMAT(estb, '%m') from Collegedetail; +-------------------------+ | DATE_FORMAT(estb, '%m') | +-------------------------+ | 05 | | 10 | | 09 | | 07 | | 07 | +-------------------------+ 5 rows in set (0.00 sec) mysql> Select DATE_FORMAT(estb, '%M') from Collegedetail; +-------------------------+ | DATE_FORMAT(estb, '%M') | +-------------------------+ | May | | October | | September | | July | | July | +-------------------------+ 5 rows in set (0.10 sec)
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使用两个不同的函数,YEAR() 和 MONTH()
它将使用两个不同的函数分别提取年份和月份。为了理解这一点,请考虑以下使用“Collegedetail”表中的数据的示例:
mysql> Select YEAR(estb) AS 'Year', MONTH(estb) As 'MONTH' From collegedetail; +------+-------+ | Year | MONTH | +------+-------+ | 2010 | 5 | | 1995 | 10 | | 1994 | 9 | | 2001 | 7 | | 2010 | 7 | +------+-------+ 5 rows in set (0.00 sec)
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