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" )