mysql_num_rows

Anon

I am getting a "Warning: 0 is not a MySQL result index in..." error for

$result = mysql_num_rows($query);

where $query is a SELECT mysql query. $result is allowed to be zero, right? What is going on here? Thanks.

Anon

I wonder if you should have used the result index rather than $query? First you use the function mysql_query($query) that returns a result index e.g.

$result = mysql_query($query);

then

$num = mysql_num_rows($result);

$result would also be used in the function mysql_result().

Jim

jwsaund

Thanks but i think that is what i'm doing, i should have provided more code:

mysql_connect($this->server, $this->db_user, $this->db_pass);
mysql_select_db($this->database);
$query = mysql_query("select id from login where username = '$username' and password = '$password'");

$result = mysql_num_rows($query);

Any more ideas?

Anon

Sorry to be of no use last time. I'm used to getting that error though, at times. So, given your code so far is ok, and you are connected ok to the database (you can use the 'or die'to get error messages e.g.

mysql_connect($this->server, $this->db_user, $this->db_pass) or die ("Sorry cant connect to database");

that lets you know when you havn't connected etc. etc. - please forgive me if you know this already :-) )

then, perhaps you could use $result within a logical construct e.g.

if ($result) { do something } - this would perhaps then not send you the error message and you could then use an else { do something else } in order to do something else if the query turns up 0 results.

An alternative might be to turn the error message off by using the @ before the function, (I think), though I dont do this myself.

Any use?

Jim

Anon

No. A result index of 0 means that there was an error in the query.

After,

$result=mysql_query($query);

you should have:

print mysql_error();

So that, if there is an error you'll get the message returned by mysql about what it didn't like with your query.