/**
* Initialize a query builder to perform an AVG query on the database
*
* @param string $table The table name
* @param string $field The field name to find average
* @param string $alias The optional field alias; defaults to "avg"
*
* @return object QueryBuilder
*/
function db_avg($table, $field, $alias = null)
{
$qb = new QueryBuilder($table);
return $qb->avg($field, $alias ? $alias : 'avg');
}
