Counting occurrences using Toxi solution - php

Question

I'm new to mysql.
I wanted to develop a simple tagging system for my blog and came across this "Toxi" Solution of making 3 tables.
So, I have 3 tables:
`blog` containing `id` and `title`.
`blog_tags` containing `id` and `tags_id` and `blog_id`.
`tags` containing `id` and `name`.
tags_id is connected to Internal Relation to id in tags table.
Similarly, blog_id is connected to Internal Relation to id in blog table.
So, when in my function (where I get the array of all tags pertaining to a single blog) I execute a query for example (passing blog id as the parameter in the function),
$result = mysql_query("SELECT tags_id FROM blog_tags WHERE blog_id = '".$id."'");
$tags = array();
if($result === FALSE) {
die(mysql_error()); // TODO: better error handling
}
while($row = mysql_fetch_assoc($result)) {
$tags[] = I don't know what should come over here?
}
return $tags;
Or is there any other way to execute queries in this Toxi implementation?

Answer 1

UPDATED You need a simple JOIN. Your query should look like
SELECT bt.tags_id, t.name
FROM blog_tags bt JOIN tags t
ON bt.tags_id = t.id
WHERE bt.blog_id = n -- < n is an id of a blog
Here is SQLFiddle demo.
Now php is pretty straightforward
$sql = "SELECT bt.tags_id, t.name
FROM blog_tags bt JOIN tags t
ON bt.tags_id = t.id
WHERE bt.blog_id = $id";
$result = mysql_query($sql);
if($result === FALSE) {
die(mysql_error()); // TODO: better error handling
}
$tags = array();
while($row = mysql_fetch_assoc($result)) {
$tags[] = $row['name'];
}
...
On a side note: switch to PDO or mysqli. mysql_* extension is deprecated. In PDO you can use a syntactic sugar fetchAll(). And more importantly learn to use prepared statements. Right now your code is vulnerable to sql-injections.