This is the line:

$row = db_fetch_object($result);

While $result is valid but $row is getting a null value which I've checked with is_null.

As per this function's @return value, it can only return FALSE in failure.

Also mysql_db_object states the same.

What could be the reason it is returning null?

  • 1
    FALSE !== NULL ...
    – Jimajamma
    Dec 21, 2011 at 20:04
  • What is the actual query?
    – Malks
    Dec 21, 2011 at 21:45

1 Answer 1


Actually, db_fetch_object() could also return NULL, contrary to what the documentation says. The documentation assumes you aren't passing to the function a value that for PHP is equivalent to FALSE, for example NULL, an empty array, or an uninitialized variable. If the function gets a value that for PHP is equivalent to FALSE, the function will not execute any instruction, and it will return NULL.

function db_fetch_object($result) {
  if ($result) {
    return mysql_fetch_object($result);

The same is true for other database engines, for example PostgreSQL, which uses the following function.

function db_fetch_object($result) {
  if ($result) {
    return pg_fetch_object($result);

This is usually not a problem, since the function should normally be called as in the following snippets.

 if ($category = db_fetch_object(db_query('SELECT cid, title, block FROM {aggregator_category} WHERE cid = %d', $id))) {
    $block['subject'] = check_plain($category->title);
    $result = db_query_range('SELECT i.* FROM {aggregator_category_item} ci LEFT JOIN {aggregator_item} i ON ci.iid = i.iid WHERE ci.cid = %d ORDER BY i.timestamp DESC, i.iid DESC', $category->cid, 0, $category->block);
    $read_more = theme('more_link', url('aggregator/categories/' . $category->cid), t("View this category's recent news."));
  while ($item = db_fetch_object($result)) {
    $items[] = theme('aggregator_block_item', $item);

In both the cases, the control statements will not be executed, since for them NULL is equivalent to FALSE.

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