Question

If a user creates a group and that group doesn’t exist, then create that group; but if it already exists, send a message saying so.

This my code. It inserts into my database but cannot check if a group already exists.

<?php

    mysql_connect('localhost','root','');

    mysql_select_db('test');

    $result = mysql_query('SELECT * FROM groups WHERE name!="'.misc::escape($_POST['name']).'"');

    if(mysql_num_rows($result) == 0)
    {

       $sql="INSERT INTO groups(name) VALUES ('$_POST[name]')";

       mysql_query($sql);

       $select_result=mysql_query("SELECT * FROM groups WHERE name='$_POST[name]' ");

       $row = mysql_fetch_assoc($select_result);

       echo($row['id']);

    }

    else

    {

      echo("this group exist");

    }

?>

Answer 1

You can use mysql_num_rows to count the number of rows returned by a query:

$result = mysql_query("SELECT * FROM groups WHERE name != '$_POST[name]'");
if (mysql_num_rows($result) == 0)
{
     // create new group
}
else
{
     // print an error
}