get basic stats from a table.

        $arPgUser = array("user"=> "postgres","host"=>"localhost","dbname"=>"dev","password" => "i1m2a3p4o5o6p7e8r9");
        $connStr  = getConnStr($arPgUser);
        $conn     = pg_connect($connStr);
        $table    = "books";

        $sqlGetSchema = "select column_name,data_type from information_schema.columns where table_name = '{$table}'";
        $res          = pg_fetch_all(pg_query($conn,$sqlGetSchema));
        $columns      = array_map("sqlFieldStats",($res));

        $sqlBuildStats= sqlBuildStats($columns,$table);
        $res          = pg_fetch_all(pg_query($conn,$sqlBuildStats));
        print_r($res);

        pg_close($conn);

function sqlBuildStats($columns,$table){

        $sqlColumns = implode(",\n",$columns);
        $sql = "
        select
                $sqlColumns
        from
                $table
        ";
        echo "{$sql}\n";

return trim($sql);
}

function sqlFieldStats($arSchema){

        switch($arSchema['data_type']){

                case "text":
                        return "count(distinct({$arSchema['column_name']})) as dist_{$arSchema['column_name']}";
                break;

                case "numeric":
                        return "sum({$arSchema['column_name']}) as sum_{$arSchema['column_name']}";
                break;
        }
}


function getConnStr($arPgUser){

        $connStr = "";
        foreach ($arPgUser as $key => $value)
                $connStr.= "{$key} = {$value} ";

return $connStr;
}