select STR_TO_DATE('18.05.2015 23:59:59', '%d.%m.%Y %H:%i:%s')
       -
       STR_TO_DATE('16.05.2015 23:59:57', '%d.%m.%Y %H:%i:%s')

select   date(t.time)
               ,t.ts
          ,SUM(t.velocity)
          FROM (
                  select t.*
                        ,t.time
                        ,t.velocity
                        from table t
                      where 1 = 1
                        and t.time between STR_TO_DATE('13.05.2015 00:00:00', '%d.%m.%Y %H:%i:%s')
                                       and STR_TO_DATE('18.05.2015 23:59:59', '%d.%m.%Y %H:%i:%s')
               ) t
         where 1 = 1
         group by date(t.point_time)
                 ,t.ts

select date(t.time)
      ,t.ts
      ,SUM(t.velocity)
  FROM (
    select t.*
      from (
        select t.*
              ,t.time
              ,t.velocity
              from table t
            where 1 = 1
              and t.time between STR_TO_DATE('13.05.2015 00:00:00', '%d.%m.%Y %H:%i:%s')
                             and STR_TO_DATE('18.05.2015 23:59:59', '%d.%m.%Y %H:%i:%s')
           ) t
       ) t
 where 1 = 1
 group by date(t.point_time)
         ,t.ts

select  date(t.time)
       ,t.ts
       ,sum( case when n_sec_dif > 60 * 5
                  then n_sec_dif * 60 /
                  when t.n_velocity_prev = 0 and t.n_velocity = 0
                  then n_sec_dif * 60 
               end
           )
         FROM (
           SELECT t.*
                 ,TIME_TO_SEC(TIMEDIFF( t.t_time, t.t_time_prev )) AS n_sec_dif
             FROM (  select gp.*
                            ,(select max(gp2.time)
                                from tabl          gp2
                               where 1 = 1
                                 and gp2.time between STR_TO_DATE('13.05.2015 00:00:00', '%d.%m.%Y %H:%i:%s')
                                                        and STR_TO_DATE('18.05.2015 23:59:59', '%d.%m.%Y %H:%i:%s')
                                 and gp2.ts = gp.ts
                                 and gp2.time < gp.time                     
                                                        
                             )                                                     as t_time_prev
                           ,gp.time                                         as t_time
                           ,(select max(gp2.velocity)
                               from tabl          gp2
                              where 1 = 1
                                and gp2.time between STR_TO_DATE('13.05.2015 00:00:00', '%d.%m.%Y %H:%i:%s')
                                                       and STR_TO_DATE('18.05.2015 23:59:59', '%d.%m.%Y %H:%i:%s')
                                and gp2.ts = gp.ts
                                and gp2.time < gp.time                     
                                                       
                            )                                                     as n_velocity_prev
                           ,gp.velocity                                           as n_velocity  
                       from      tabl       gp
                     where 1 = 1
                       and gp.time between STR_TO_DATE('13.05.2015 00:00:00', '%d.%m.%Y %H:%i:%s')
                                             and STR_TO_DATE('18.05.2015 23:59:59', '%d.%m.%Y %H:%i:%s')
                  ) t
            WHERE 1 = 1
               ) t
         where 1 = 1
         group by date(t.time)
                 ,t.ts