The scenario is described here:

mydb=> create table test (   name char(50), phone char(8) );
mydb=> insert int test values ('Renato', '3434343');

query.php:

<?
$conn = pg_connect("dbname=mydb");
$result = pg_exec($conn, "select name, phone from test")
$arr = pg_fetch_array($result, 0);
echo $arr["name"];
?>

( nothing gets printed out. but if I use $arr[0] I get 'Renato')