How to do SQL's GROUP BY using PHP? - php

Question

I'd like to SELECT rows from a database table and group them using PHP instead of SQL based on a parameter (in this case by item).
SQL:
Clothes table
id item owner
1 shoes joe
2 pants joe
3 hat joe
4 pants joe
5 hat tom
SELECT * from Clothes where owner='joe'
1 shoes joe
2 pants joe
3 hat joe
4 pants joe
Here's how I'd like the results to look after using PHP instead of SQL's GROUP BY item
PHP :
1 shoes joe
2 pants joe //count 2
3 hat joe
I'm sure there is a PHP array function for this I'm just not familiar, thoughts?

Answer 1

The easiest way is to exploit the uniqueness of array keys:
$grouped = array();
while ($row = $db->fetchResult()) { // or however you get your data
if (isset($grouped[$row['item']])) {
$grouped[$row['item']]['count']++;
} else {
$grouped[$row['item']] = $row + array('count' => 1);
}
}

Answer 2

Using pseucode for the database access functions, I believe this should work:
$sql = "SELECT * from Clothes where owner='joe'";
$res = query($sql);
$arr = array();
while ($row = $res->fetch())
{
$arr[] = $row['item'];
}
$arr = array_unique($arr);
You should note that this might give you a "sparse array" (in other words, there may be gaps in the keys). And as said in the comments, it's usually better to do this in SQL if you have that option. Even if that means executing two similar queries.

Answer 3

function group($items, $field) {
$return = array();
foreach ($items as $item) {
$key = $item[$field];
if (isset($return[$key])) {
$return[$key]['count']++;
} else {
$return[$key] = $item;
$return[$key]['count'] = 1;
}
}
return $return;
}
print_r(group($results, "item"));