Question

Help me please. How can I select sum of time in seconds by today?
For example I have some table:

online | offline | ....
 10:33 | 12:08 | ...
 13:10 | 13:34 | ...

And I need receive sum of this periods in seconds (or minutes – it’s not important).
Thanks!

Answer 1

def secounds
     (self.offline-self.online).to_i # will give you the time in secounds
end

then you can use this for blocks

sum=Integer.new
Model.where(_your conditions_).each do |instance|
     sum+=instance.secounds
end
sum # << the secounds of all the data you selected using the weher coondition

// Ahh and one thing. Theres an unwriten law that you never ever create a column for data you can calculate out of other columns.

On DB only:

Model.sum("offline-online")
Model.where("my condition").sum("offline-online") # also with conditions....