single variable user validation

[Anon]

Is there a way to use php to check a mysql database for a single existing entry? I posted a message about using two fields, but ideally I would be able to have someone enter their email address, the script would check to see if their address exists in the db, and if so, redirect them to various html pages depending on where I want each different user to be able to go. Thank you very much for any help.

[mattw]

Sure....

//get email address into a var named $email
//do your db connection

$query = "SELECT * FROM table WHERE email='".$email."'";
$result = mysql_query($query);
if(mysql_num_rows($result) > 0) {
//do what you want to do if match
} else {
//do what you want to do if not match
}

Hope that helps,
Matt Wade
codewalkers.com

[Anon]

More efficient is

$query = "SELECT COUNT(*) AS c FROM table WHERE email='".$email."'";
$result = mysql_query($query);
if(mysql_result($result,0,'c') > 0) {
//do what you want to do if match
} else {
//do what you want to do if not match
}

Otherwise you're pulling all the data of all the matches out of the database just to see how many matches there were, when you could just ask the database for exactly that.

[Anon]

Does anyone know how I would add a header to this snippet, so when the php page is called, it goes to an htm page with a form, then the user enters thier email and submits, then the connect sequence? Thanks muchas.

Matt Wade wrote:

Sure....

//get email address into a var named $email
//do your db connection

$query = "SELECT * FROM table WHERE email='".$email."'";
$result = mysql_query($query);
if(mysql_num_rows($result) > 0) {
//do what you want to do if match
} else {
//do what you want to do if not match
}

Hope that helps,
Matt Wade
codewalkers.com

[Anon]

Does anyone know how I would add a header to this snippet, so when the php page is called, it goes to an htm page with a form, then the user enters thier email and submits, then the connect sequence? Thanks muchas.

Hayley Watson wrote:

More efficient is

$query = "SELECT COUNT(*) AS c FROM table WHERE email='".$email."'";
$result = mysql_query($query);
if(mysql_result($result,0,'c') > 0) {
//do what you want to do if match
} else {
//do what you want to do if not match
}

Otherwise you're pulling all the data of all the matches out of the database just to see how many matches there were, when you could just ask the database for exactly that.