How to ignore duplicate rows when echoing mysql query result - php

Question

I trying to make tag cloud system and i enter the tags in one table with "name" and "product_id".
I make that may have multiple same tags everyone for different product.
My problem is that when echo the tags from the table it show me all tags,this is good,but the repeated tags are in that count. I need to echo repeated tags only once, but i don't know how to make that.
Here is and my code that showed and repeated tags.
$id = $_GET['catid'];
$sql = "SELECT * FROM tags_group";
$result = mysql_query($sql) or die(mysql_error());
while ($row = mysql_fetch_array($result)) {
//echo $row['name'];
$id = $row['id'];
$sql1 = "SELECT * FROM tags WHERE tag_group='$id'";
$result1 = mysql_query($sql1);
while ($row1 = mysql_fetch_array($result1)) {
$name = $row1['tag_name'];
$sql2 = "SELECT * FROM tags WHERE tag_name='$name'";
$resut2 = mysql_query($sql2);
$rows = mysql_num_rows($resut2);
echo $row1['tag_name'] . '(' . $rows . ')' . '<br>';
// echo $row1['tag_name'].$rows.'<br>';
}
echo '<br>';
}

Answer 1

You have to use the DISTINCT keyword do avoid duplicates:
SELECT DISTINCT * FROM tags_group
As I mentioned in the comments above, you should stop using mysql_* functions. They're being deprecated. Instead use PDO (supported as of PHP 5.1) or mysqli (supported as of PHP 4.1). If you're not sure which one to use, read this article.
UPDATE
It also looks like you're using nested queries, rather than joining your tables and retrieving the results. Try this instead:
$id = $_GET['catid'];
$sql = "SELECT tags.tag_name, count(*) AS name_count FROM tags
INNER JOIN tags_group
ON tags.tag_group = tags_group.id
GROUP BY tag_name";
$result = mysql_query($sql) or die(mysql_error());
while ($row = mysql_fetch_array($result)) {
$name = $row['tag_name'];
$rows = $row['name_count'];
echo $name . '(' . $rows . ')' . '<br>';
// echo $row['tag_name'].$rows.'<br>';
}
echo '<br>';
Here I don't use DISTINCT but GROUP BY allows you to aggregate the count for each distinct row (based on the GROUP BY column).
Take a look at this diagram to better understand how joins work.