php count函数没有在mysql_fetch_assoc上显示正确的计数

Question

I have got data from mysql_fetch_assoc stored in to an array using this command

if(mysql_num_rows($data) > 1){
                while($row = mysql_fetch_assoc($data)){
                    $ndata[] = $row;
                }
            } else {
                $ndata = mysql_fetch_assoc($data);
            }

Now when I use count on $ndata, it retuns 1; although it is empty.

When I run mysql_num_rows on the returned data it retuns 0 rows. But when I convert the data to $ndata and then run count on that it returns 1. I want it to return the number of rows.

Thanks

Can someone please explain why is there a problem and how to fix it?

Answer 1

Your logic is wrong: you don't test for the case that mysql_num_rows($data) == 0. If this is the case, your code executes the same path as when the number of rows is 1 ($ndata = mysql_fetch_assoc($data);). But there are no more rows to return (there are no rows at all), so mysql_fetch_assoc returns false. And count(false) returns 1, because that's how count works.

Do it this way:

$rows = mysql_num_rows($data);
if($rows == 0) {
    return null;
}
else if($rows == 1){
    $ndata = mysql_fetch_assoc($data);
} else {
    while($row = mysql_fetch_assoc($data)){
        $ndata[] = $row;
    }
}

You can either return null or array() in the first if branch; these are the only two values for which count returns 0.