一个奇怪的mysql_fetch_（assoc，array，object）错误[重复]

Question

Possible Duplicate:
php warning mysql_fetch_assoc

I have a weird problem about my script. It returns always error for mysql_fetch_array or mysql_fetch_assoc. I have used mysql_fetch many times in my project and I checked for this error many times but I am blind about what is happening. Is there something wrong about my script?

My functions aim is learning the biggest value of specified mysql field.

Here is the function:

function nextIncrement($table,$field) {
    $sql = mysql_query("SELECT '$field' FROM '$table' ORDER BY '$field' DESC LIMIT 0,1");
    while($row = mysql_fetch_assoc($sql)) {
        $next = $row[$field];
    }
    $next = (int)$next;
    return $next;
}

Warning: mysql_fetch_assoc(): supplied argument is not a valid MySQL result resource ...

Answer 1

Most likely, your mysql_query() returned false for some reason.

See the manual for a list of possible values that mysql_query() can return.

Do a echo mysql_error(); to see what's wrong.