Select Where using character varying ??

Hi Guys

 

I am printing names into a combo box and posting the variable. I try and use the name ($Sem) in an SQL statement; WHERE name = $Sem; but I get an error which is displayed near the end of this message. Are we able compare php string to postgresql character varying??  not sure how else to do the selection

 

 

$conn = pg_Connect("host=localhost dbname=#### user=#### password=####");
   if (!$conn) {echo "An database connection error occurred.\n"; exit;}

 

 

// e.g. $Sem = "seminar one";

 

$Sem = $_POST['Seminars'];

 

 

$Sem_No = pg_Exec($conn,"SELECT seminar_id FROM seminar WHERE name = $Sem");
 if (!$SemNo) {echo "A query error occurred in retreiving the selected seminar's ID <br>"; /*exit;*/}
$Sem_No = pg_Result($Sem_No, 0);

 

// Error Message

 

Warning: pg_exec() [function.pg-exec]: Query failed: ERROR: syntax error at or near "one" at character 54 in /home/bdwilko/public_html/jet/form/insertP.php on line 56
A query error occurred in retreiving the selected seminar's ID

 

 

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