How do I add all of a table in MySQL for example ..
I have the table tb_comment
, so I want to add in each post(id_mark)
the amount of rate that will have the total.
For example, id_user 20
has the rate of 4 in id_mark 10
and id_user 21
has the rate of 5 in id_mark 10
and will give 9 to the total how do I select this in PDO?