mysql query logic in codeigniter - php

Question

I have two mysql tables memes and votes. Sample data is give below
Memes table
Votes table
vote = 1 is for upvote and vote = 0 is for downvote.
I want result something like this
To calculate up and down votes for each record.
Here is my code only for get records from memes table.
function loadAllMemes($categoryID,$sortby, $page,$perpage)
{
$data = array();
$this->db->select("*");
$this->db->from("memes");
$this->db->limit($perpage, $page);
if($categoryID > 0)
{
$this->db->where("categoryid",$categoryID);
}
if($sortby != "")
{
if($sortby == "recently")
{
$this->db->order_by("date","DESC");
}
else if($sortby == "popular")
{
$this->db->order_by("views","DESC");
}
}
$query = $this->db->get();
return $query->result();
}
Any help will be appreciated. Thanks

Answer 1

select Memes.*, sum(vote) upvote, sum(if(vote = 0, 1, 0)) downvote from memes
join vote on memes.id = memeid
group by memeid
This is not tried out. So kndly excuse if there is any syntax error
NOTE : This is purely in sql. Please do necessary things to convert for codeigneter

Answer 2

For Mysql you can directly put your condition us sum function and this will result a boolean 0/1 and you can use it your query as below
SELECT
m.*,
SUM(v.vote = 1) upvotes, /* this equal to SUM(CASE WHEN v.vote = 1 THEN 1 ELSE 0 END) */
SUM(v.vote = 0) downvote
FROM memes m
JOIN vote v ON m.id = v.memeid
GROUP BY m.id
For active record you can write above query as
$this->db->select('m.*,SUM(v.vote = 1) upvotes,SUM(v.vote = 0) downvote',FALSE)
->from('memes m')
->join('vote v','m.id = v.memeid ')
->group_by('m.id')
->get()
->result();

Answer 3

Quick solution would be by using subquery, although, I think join would be more efficient here.
SELECT
m.id,
m.title,
m.path,
m.date,
m.categoryid,
m.views,
(SELECT COUNT(*) FROM votes WHERE vote = '1' AND memeid = m.id) upvotes,
(SELECT COUNT(*) FROM votes WHERE vote = '0' AND memeid = m.id) downvotes
FROM memes m