Question

I was wondering if this

$c = mysql_num_rows(mysql_query("select * from action_6_weekly where code='$code'"));

is considered valid PHP?

Or do I need to do the following?

$r = mysql_query("select * from action_6_weekly where code='$code'");
$c = mysql_num_rows($r);

this is what i am actually doing:

if($entry == '9')
    $c = mysql_num_rows(mysql_query("select * from action_6_5pts where code='$code'")) or die ('MYSQL ERROR: '.mysql_error().' in '.__FILE__.' on '.__LINE__.'.');
elseif($entry == 'a')
    $c = mysql_num_rows(mysql_query("select * from action_6_10pts where code='$code'")) or die ('MYSQL ERROR: '.mysql_error().' in '.__FILE__.' on '.__LINE__.'.');
else
    $c = mysql_num_rows(mysql_query("select * from action_6_weekly where code='$code'")) or die ('MYSQL ERROR: '.mysql_error().' in '.__FILE__.' on '.__LINE__.'.');

if($c > 0) 
    $waiting_for_reply = false;

Answer 1

It is generally better to do it on separate lines and assign it a variable.

This way you can work with the result easier. But to get a count of rows, if that is all you are looking for, this would be better and more efficient:

$r = mysql_query("select count(id) from action_6_weekly where code='$code'");
$c = mysql_result($r, 0, 0);

Where the id is the unique identifier field to count.

EDIT:
Given that you do not care how many rows there are, just that it exists:

$r = mysql_query("select code from action_6_weekly where code='$code' LIMIT 1");
if (mysql_num_rows($r) > 0) {
    // echo it exists!
}