Re: Help for a create un trigger

[Phillip Ward]

Quote

I need to fill in a data_diff field to warn how many days I do not receive communication from the device

No, you don't.
This time-based value will change all the time (pun intended).

This is data that can be derived from other data that you already have, i.e. the date on which you last received data from each device:

select 
  a.id_Autotest
, now() - data_ultimo intervallo 
from autotest_ping a 
inner join 
( 
  select id_Autotest 
  , max( data_arrivo ) data_ultimo 
  from autotest_ping
  group by id_Autotest
) b 
on a.id_Autotest = b.id_Autotest
order by 2 desc, 1 ;

Of coourse, an index on id_Autotest and data_arrivo would help this query a lot.

Regards, Phill W.