mysql_num_rows(): supplied argument is not a valid MySQL result resource

Question

if(mysql_num_rows($result))
{
echo "no match found!";
}

it is throwing an error- Warning: mysql_num_rows(): supplied argument is not a valid MySQL result resource in D:\Hosting\6448289\html\includes\getQuestion.php on line 72

It is the error of mysql_query(), Please check this or check select query also.... — Karthik, Sep 13 '10 at 08:16
LOL no, the code *after* this line is not needed :) Although no need to show any code. the problem is clear. You have an error while query execution. Use codaddict's code to see what error you experience. — Your Common Sense, Sep 13 '10 at 08:28

score 5 · Answer 1 · edited Sep 13 '10 at 08:20

5

You need to check the return value of mysql_query

$query = 'YOUR QUERY';
$result = mysql_query($query);
if (!$result) {
    trigger_error('Invalid query: ' . mysql_error()." in ".$query);
}
// go ahead and fetch the results using mysql_num_rows.

If mysql_query fails it returns boolean false instead of a resource.

When you pass this boolean value to mysql_num_rows you get this error.

edited Sep 13 '10 at 08:20

Your Common Sense

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answered Sep 13 '10 at 08:14

codaddict

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A more concise version is `mysql_query(...) or trigger_error(mysql_error())` – Amber Sep 13 '10 at 08:19
edited code to be more useful and reliable – Your Common Sense Sep 13 '10 at 08:20

mysql_num_rows(): supplied argument is not a valid MySQL result resource

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