I am trying to insert contacts into database but does not want to duplicate already existing contact.

Not sure INSERT has WHERE CLAUSE.

Any ideas?

//Insert INTO contact database

$user_id = userid;

$sql_insert = "INSERT into `jt_members_external_contacts`
            (`j_user_id`,`contact_email`,`firstname`
            )
            VALUES
            ('$user_id','$email','$name') WHERE j_user_id !=$user_id AND contact_email != $email;";