A quick multi-table multi-field search model for CI / PHP

search_model.php

<?php

class Search_model extends CI_Model
{
    protected $tables = array(
        'users' => array( 'name', 'email' )
    );

    public function run($search)
    {
        $queries = array();

        foreach ($this->tables as $table => $fields)
        {
            $wheres = array();
            $query = '(SELECT ';
            $query .= implode(', ', $fields);
            $query .= ", '" . $table . "' AS type";
            $query .= " FROM " . $table;

            foreach ($fields as $field)
            {
                $wheres[] = $field . ' LIKE "%' . $search . '%"';
            }

            $query .= ' WHERE ';
            $query .= implode(' OR ', $wheres);
            $query .= ')';

            $queries[] = $query;
        }

        $result = $this->db->query(implode(' UNION ', $queries));
    }
}