MAKEDATE(year,dayofyear)
返回给定年份和一年中的天值的日期。一年中的天必须大于0,否则结果为NULL。
mysql> SELECT MAKEDATE(2001,31), MAKEDATE(2001,32); +---------------------------------------------------------+ | MAKEDATE(2001,31), MAKEDATE(2001,32) | +---------------------------------------------------------+ | '2001-01-31', '2001-02-01' | +---------------------------------------------------------+ 1 row in set (0.00 sec)