Determine if an entry exists

[klik]

Hi,

I would like to check if a value held in variable $username exists.

Here is some code:

/* Make sure username is in database */
	if ($username DOES NOT EXIST IN FIELD username COLUMN, WITHIN DATABASE CALLED cms_users){
		echo "<font color=\"#FF3300\">Username does not exist</font><br><br>";
		return false;
	}

Obviously, the capitalised line, needs some code put in, but I'm not sure what code will give me the result I require. I'm pretty sure this is relatively simple to overcome.

Any help would be appreciated, as always.

-Klik

[bubblenut]

What's the table structure?
What database system are you using?

[klik]

I'm using mySQL.

Here is the table I created.

CREATE TABLE cms_users (
user_id int(25) NOT NULL auto_increment,
username varchar(25) NOT NULL default '',
password varchar(25) NOT NULL default '',
email varchar(200) NOT NULL default '',
show_email enum('0','1') NOT NULL default '1',
location varchar(25) NOT NULL default '',
fav_rapper varchar(25) NOT NULL default '',
info varchar(250) NOT NULL default '',
user_level enum('0','1','2','3') NOT NULL default '0',
reg_date datetime NOT NULL default '0000-00-00 00:00:00',
last_login datetime NOT NULL default '0000-00-00 00:00:00',
user_points int(255) NOT NULL default '0',
PRIMARY KEY (user_id)
) TYPE=MyISAM COMMENT='Membership Information';

[devinemke]

$result = mysql_query("SELECT * FROM cms_users WHERE username = '$username'");
if (mysql_num_rows($result)) {echo $username . ' is in the table';}
else {echo $username . ' is not in the table';}

[bubblenut]

This'll do it. You really, really, really, really should have a read of the manual pages for all the functions I've used though, so you get a full and clear understanding of what's happening.
Check out the manual.

$conn=mysql_connect($host, $user, $pass) or die(mysql_error());
mysql_select_db($db, $conn);
$sql="SELECT count(*) FROM cms_users WHERE username='$username'";
$res=mysql_query($sql, $conn) or die($sql."<br />\n".mysql_error());
list($count)=mysql_fetch_row($res);
if($count!=1) {
  echo "<font color=\"#FF3300\">Username does not exist</font><br><br>";
  return false; 
}

HTH
Bubblenut

[klik]

Thank you both.

And I will read up on the functions, as always.