¿Cómo se comprueba si el valor de una columna es nulo? Código de ejemplo:PHP PDO fetch null
$db = DBCxn::getCxn();
$sql = "SELECT exercise_id, author_id, submission, result, submission_time, total_rating_votes, total_rating_values
FROM submissions
LEFT OUTER JOIN submission_ratings ON submissions.exercise_id=submission_ratings.exercise_id
WHERE id=:id";
$st = $db->prepare($sql);
$st->bindParam(":id", $this->id, PDO::PARAM_INT);
$st->execute();
$row = $st->fetch();
$this->total_rating_votes = $row['total_rating_votes'];
if($this->total_rating_votes == null) // this doesn't seem to work even though there is no record in submission_ratings????
{
...
}
¿Qué contiene '$ row ['total_rating_votes'];'? –
$ row ['total_rating_votes']; debe contener NULL ya que no existen registros en la tabla submission_ratings. Lo he verificado ejecutando la consulta en mysqladmin. – Jacob
Si no hay registros, entonces $ row ['total_rating_votes'] no está configurado. Haz una print_r ($ fila). Debería verificar el valor de retorno de execute, que será el número de registros encontrados. –