小编Jac*_*cob的帖子

请问,如何wchar_t*在c ++中找出类型变量的长度？

代码示例如下:

wchar_t* dimObjPrefix = L"retro_";

我想知道dimObjPrefix包含多少个字符

如何检查列值是否为空？示例代码:

$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????
{
...
}