Question

Is it possible for $variable to take different values at the point of the INSERT query? If my statement is false, how can I achieve this.
Thank you.

  if(isset($_GET['id'])) {
   $variable = "Foo" ;
  }

  elseif (!isset($_GET['id'])) {
  $variable = "Bar" ;
  }

$sql  = mysql_query("INSERT INTO tbl
             tbl_id, variable
              VALUES('$id', '$variable'");

Answer 1

One variable can hold only one value at once and in your code it’s valid. If id is available it’ll have Foo, otherwise it’ll have Bar and alternatively you can write it in one line as follows:

$variable=isset($_GET['id']) ? 'Foo' : 'Bar';

Then you can use your $variable variable later in your script. It’ll contain at least one value Foo or Bar.