- array_column: documentation ( source)
- in_array: documentation ( source)
<?php
$array = array(
array('name' => 'number1', 'number' => '0612345675'),
array('name' => 'number2', 'number' => '0634345675'),
array('name' => 'number3', 'number' => '0634378675')
);
$valueToFind = '0634345675';
if (in_array($valueToFind, array_column($array, 'number'))){
echo 'found';
}