selectFunctionField	(		$function,
			$key,
		array	$conditions
	)

Select function.

Performs a SQL function such as COUNT(*), SUM(*), ... on a table field for those rows meeting conditions.

Parámetros

string	$key	The field name. Must be SQL safe.
array	$conditions	Each entry is a condition. A condition is an array of three therms.

                                                                          {
    $functions = array('COUNT', 'SUM');
    if (!in_array($function, $functions)) {
      throw new Exception('Invalid database function.');
    }
    $query = db_select($this->table, 't');
    $query->addExpression($function . '(' . $key . ')');
    foreach ($conditions as $condition) {
      if (count($condition) == 3) {
        $query->condition($condition[0], $condition[1], $condition[2]);
      }
      elseif (count($condition) == 2) {
        $query->condition($condition[0], $condition[1]);
      }
    }
    return $query->execute()->fetchField();
  }