The following example demonstrates how to return an associative array
grouped by the values of the specified column in the result set. The
array contains three keys: values apple and
pear are returned as arrays that contain two
different colours, while watermelon is
returned as an array that contains only one colour.
<?php
$insert = $dbh->prepare("INSERT INTO fruit(name, colour) VALUES (?, ?)");
$insert->execute('apple', 'green');
$insert->execute('pear', 'yellow');
$sth = $dbh->prepare("SELECT name, colour FROM fruit");
$sth->execute();
/* Group values by the first column */
var_dump($sth->fetchAll(PDO::FETCH_COLUMN|PDO::FETCH_GROUP));
?>
The above example will output:
array(3) {
["apple"]=>
array(2) {
[0]=>
string(5) "green"
[1]=>
string(3) "red"
}
["pear"]=>
array(2) {
[0]=>
string(5) "green"
[1]=>
string(6) "yellow"
}
["watermelon"]=>
array(1) {
[0]=>
string(5) "green"
}
}