mysql中将时间作为where条件的判断格式

方法一：

SELECT
	a.`activity_id`,
	a.`activity_name`,
	a.`province`,
	a.`office_place`,
	a.`office_leader`,
	c.`activity_type_name`,
	a.`activity_type_id`,
	a.`activity_place`,
	a.`activity_time`,
	a.`person_num`,
	a.`activity_sum`,
	a.office_leader,
	b.`username` createName 
FROM
	activity_info a
	LEFT JOIN sys_user b ON a.user_id = b.user_id
	LEFT JOIN activity_type_info c ON c.activity_type_id = a.activity_type_id 
WHERE
	activity_time > DATE_FORMAT( '2018-01-01', "%Y-%m-%d" ) 
	AND activity_time < DATE_FORMAT( '2018-12-31', "%Y-%m-%d" ) 

方法二：

SELECT
	a.`activity_id`,
	a.`activity_name`,
	a.`province`,
	a.`office_place`,
	a.`office_leader`,
	c.`activity_type_name`,
	a.`activity_type_id`,
	a.`activity_place`,
	a.`activity_time`,
	a.`person_num`,
	a.`activity_sum`,
	a.office_leader,
	b.`username` createName 
FROM
	activity_info a
	LEFT JOIN sys_user b ON a.user_id = b.user_id
	LEFT JOIN activity_type_info c ON c.activity_type_id = a.activity_type_id 
WHERE
	activity_time BETWEEN DATE_FORMAT( '2018-01-01', "%Y-%m-%d" ) 
	AND DATE_FORMAT( '2018-12-31', "%Y-%m-%d" )