Question

I want to set a cron job that will execute every 15 minutes. Before going into deep description of these query I’ll explain how my database works.

I have 2 tables ‘stories‘ and ‘votes‘. All information about article like title, category etc. is stored in the ‘stories‘ table. It’s not a big surprise that all the votes related to article are stored in a ‘votes‘ table. In the votes table there is a field named ‘item_name‘ which corespondents to the ‘id‘ of article that is in ‘stories’ table. Finally, in ‘stories‘ table I have a field named ‘showing‘ which is by default set to 0. And I want to change it to different values depending on how many votes article has, but more about it latter.

Here is a structure of my database:

Stories table

---

Votes table

---

Ok now when I cleared database structure lets get down to my question. I need a query that would look at all articles where showing=0 and sum up votes that corespondent to a particular article. If sum of votes = 10 than set showing=1 if sum of votes = -10 than set showing=2. I don’t know how such query would look, I really don’t :/
So could anyone suggest a solution please?

Addition: I asked similar question before and some people suggested trigger’s or updating database each time a vote is cast. But I would rather check it every 15 min with cron job. )))

EDIT: Just to give you more understanding of how it works )))

For example this row from ‘stories’ table:

id| 12
st_auth | author name
st_date | story date
st_title| story title
st_category| story category
st_body| story body
showing| 0 for pending, 1 for approved and 2 for unapproved

Co responds to this one from ;votes’ table:

id| 83
item_name| 12 (id of article)
vote_value| 1 for upvote -1 for downvote
etc…

Answer 1

select sum(vt.vote_value), vt.item_name
from Votes vt
join stories st on st.id = vt.item_name
and st.showing = 0
group by vt.item_name

This should give you all the articles with showing 0 and total vote value. After that you can process them row by row and update voting if needed.

Added:
I am not a PHP programmer, I mostly do PERL, but I guess it has to be something like this:

<?php 
    $query = "select sum(vt.vote_value) as vote_value, vt.item_name from Votes vt join stories st on st.id = vt.item_name and st.showing = 0 group by vt.item_name";
    $result = mysql_query($query); 
    while($row = mysql_fetch_array($result))
    {
        if($row['vote_value'] > 9) {
            $showing = 1;
        }
        else if($row['vote_value'] < -9) {
            $showing = 2;
        }
        else {
            $showing = 0;
        }
        $query2 = "UPDATE `stories` SET `showing` = $showing WHERE `id` = '".$row['item_name']."'";
        mysql_query($query2); 
    }
?>