检查MYSQL以查看是否已存在条目，否则

Question

Hi I have a long page of code with multiple if else statemets, what i would like to do is check a database to see if that Ip address is already in the table

currently i am doing it like this

     $result = mysql_query("SELECT * FROM masterip_details WHERE    ip_address='$ip_address' AND client_id='$client_id'") or die(mysql_error());
     $num_rows = mysql_num_rows($result);
    //IF THE RESULT IS MORE THAN 0, THIS MEANS THAT THEY ARE A RETURNING VISITOR
    if( $num_rows > 0 ) {
         /// Add returning Script here  

    }  else {
        //Add code

         }

Is there a way i could do this with out the if else statement?, so for example if the record was in the database just return a value of 1.

Thanks, any suggestions would be appreciated.

Answer 1

You can use count to get the number of rows with that value.

$result = mysql_query("SELECT count(*) FROM masterip_details WHERE    ip_address='$ip_address' AND client_id='$client_id'") or die(mysql_error());

return $result > 0;  //returns a boolean

This way you will get a 0 if the value doesn't exist on the database and a number higher than 0 if it does.

Answer 2

Make use of SELECT IF EXISTS on MySQL.

SELECT IF( EXISTS(
             SELECT *
             FROM  masterip_details
             WHERE `ip_address`=? AND `client_id`=?), 1, 0)