EXTRACT(unit FROM date)
EXTRACT() 函数使用同种单位指示符如DATE_ADD()或DATE_SUB()但是它从日期提取，而不是执行日期计算的部分。
mysql> SELECT EXTRACT(YEAR FROM '1999-07-02'); +---------------------------------------------------------+ | EXTRACT(YEAR FROM '1999-07-02') | +---------------------------------------------------------+ | 1999 | +---------------------------------------------------------+ 1 row in set (0.00 sec) mysql> SELECT EXTRACT(YEAR_MONTH FROM '1999-07-02 01:02:03'); +---------------------------------------------------------+ | EXTRACT(YEAR_MONTH FROM '1999-07-02 01:02:03') | +---------------------------------------------------------+ | 199907 | +---------------------------------------------------------+ 1 row in set (0.00 sec)
