List<Teacher> list = teacherService.list(newQueryWrapper<Teacher>().eq("status","available").select("name","gender","avatar_url").last("ORDER BY RAND() LIMIT 0,"+number));
4.mybatis 時間判斷
<if test="signDateStart != null & signDateStart !=''">
AND unix_timestamp(sign_date)>=unix_timestamp(#{signDateStart})</if><if test="signDateEnd != null & signDateEnd !=''">
AND unix_timestamp(sign_date)<=unix_timestamp(#{signDateEnd})</if>