$dbname = 'db1';

$db1 = pg_connect("host=$host port=$port dbname=$dbname user=$user password=$password");
if (!$db1) {
    echo "Not connected : " . pg_error();
    exit;
}

$dbname2 = 'db2';

$db2 = pg_connect("host=$host port=$port dbname=$dbname2 user=$user password=$password");
if (!$db2) {
    echo "Not connected : " . pg_error();
    exit;
}

//get the table and fields data
$table = $_GET['table'];
$table2 = $_GET['table2'];
$table3 = $_GET['table3'];
$fields = $_GET['fields'];

//turn fields array into formatted string
$fieldstr = "";
foreach ($fields as $i => $field){
    $fieldstr = $fieldstr . "$field, ";
}

//get the geometry as geojson in WGS84
$fieldstr = $fieldstr . "ST_AsGeoJSON(ST_Transform(elect_data.$table3.geom,4269))";

//create basic sql statement
$sql = "SELECT $fieldstr FROM $table
                JOIN $table2
                    ON $table.lalvoterid = $table2.lalvoterid
                JOIN elect_data.$table3
                    ON $table.cd_name = elect_data.$table3.cd_name
                GROUP BY $table2.cd";