annoying error in PHP & mySQL

[joesao]

Hello everyone,

I have a bunch of php scripts working well with mySQL on my site, but I just wrote one and I'm getting an annoying error. The code is simple:

$url = "'".$url."'";

//Get last modification date from database
$result = mysql_query("SELECT last_modified from static_pages WHERE url = $url",$db) or die("Cannot select last_modified from static_pages");

And the error message is the dreaded:

Warning: 0 is not a MySQL link index in /home/paralla/public_html/xs/includes/header_top.php3 on line 19
Cannot select last_modified from static_pages

Now what the heck does this mean? I put single quotes around $url, which is passed into the function, and this SELECT works fine in TELNET (returns 1 row, with a date). I'm accessing that like this:

$db_mod_date = mysql_result($result,0);

Which is immaterial because the script is failing on the SELECT. Now what does this mean? Obviously the select is failing, but I have no idea why.

Thanks a lot for your help.

[Anon]

Well, it seems that you did not establish the connection to the database. First, you must do

$link = mysql_connect(hostname, user, password);
mysql_select_db(database_name);

THEN you can go ahead and query. If you are doing this, go ahead and echo out a mysql_error() before the query, because your database link isn't being initiated.

Hope that helps.

Chris King

[Anon]

you are missing quotes around the variable $url... try:

$result = mysql_query('SELECT last_modified FROM static_pages WHERE url="'.$url.'",$db);

$result = mysql_query("SELECT last_modified from static_pages WHERE url = $url",$db) or die("Cannot select last_modified from static_pages");

Hope this helps

--
djloc286

[joesao]

Actually djloc286 I'm not missing the strings, you can see from my post that I took care of that.

Thanks Chris, it was the connection issue. I'm connecting in another include file (called connect.php3) that just connects...I might have to make that connection variable global ?

Thanks for the help.