var persons []domain.Person
session := engine.Where("1=1")
if param.ActivityId != nil {
session = session.And("activity_id = ?", param.ActivityId)
}
if param.Sex != nil {
session = session.And("sex = ?", param.Sex)
}
if param.Num != nil {
session = session.And("num = ?", param.Num)
}
if param.Name != "" {
name := "%" + param.Name + "%"
session = session.And("name like ?", name)
}
//注意xorm Count、Find方法执行会自动closeSession，直接使用上边的session，第二条sql的where条件会丢失，
//所以通过 session.Conds()提取where条件，放到各自的session进行执行
cnt,_:=engine.Where(session.Conds()).Count(&persons)
err := engine.Where(session.Conds()).OrderBy("create_time desc").Limit(10, 0).Find(&persons)
