MySQL错误：mysql_fetch_array期望参数1是资源[重复]

Question

Possible Duplicate:
Warning: mysql_fetch_* expects parameter 1 to be resource, boolean given error

I recently got a work from a client, where I have to change the depreciated php old code to new one. In that code I came across mysql_db_query which I converted into mysql_query but the error was given

mysql_fetch_array expects parameter 1 to be resource, boolean given

//the old code was like:

$result = mysql_db_query($mysql_db,"SELECT Hierarchy FROM MenuSystem WHERE LENGTH(Hierarchy) >= 2 AND LOCATE(" . $_SESSION['AccessLevel'] . ",AccessLevels) <> 0;");

//and my new code is :

$result = mysql_query("SELECT Hierarchy FROM MenuSystem WHERE LENGTH(Hierarchy) >= 2 AND LOCATE(" . $_SESSION['AccessLevel'] . ",AccessLevels) <> 0");

please tell me the problem

it refers to line number 11 where is the end bracket of while loop

while ($row = mysql_fetch_array($result)) {
    $ConcatHierarchy .= $row["Hierarchy"];
}

Answer 1

I can't see that the sole code will cause error. However, if you want to use $result as an array, that may rise a problem as we need to check it first. If query fails it will return a FALSE rather than a resource i.e., an array.

(I mean you use the resource later as an array actually. But yes $result is either a FALSE or a resrouce which can be used by calling mysql_fetch_array(). thanks for your comment)

Actually you can check other posts such as: mysql_fetch_array() expects parameter 1 to be resource problem

fyi, as suggested by the manual, ppl may prefer PDO now: Use of this extension is discouraged. Instead, the MySQLi or PDO_MySQL extension should be used.