Json return null - php

Question

I have the next problem doing a json to read in Andorid
(the credentials are hidden but connection going good in others files)
class reportes
{
var $parametro;
var $conexion;
function __construct(){
$host = "IP"; $DBName = "DbName";
$usuario="user"; $contrasena="pass";
$driver = "DRIVER={iSeries Access ODBC Driver};
SYSTEM=$host;Uid=$usuario;
Pwd=$contrasena;Client_CSet=UTF-8;";
$this->conexion = odbc_connect($driver, $usuario, $contrasena);
}
function consulta($parametro){
$query=
"SELECT OHSNME,OHTOT$,OHREPÑ
FROM MYDB.SANFPRD.FOMHDR
WHERE OHORDÑ= $parametro ";
echo $query."<br><br>";
if ($this->conexion == 0) {echo "Ha fallado la conexion a la BBDD </br>";}
else{
$datos = array();
$result=odbc_exec($this->conexion,$query);
while($row = odbc_fetch_object($result)){
$datos[]= $row;
}
echo json_encode($datos);
}
}//Fin funcion consulta()
}//Fin de la clase
$consultar = new reportes();
$nota_venta = $_REQUEST['parametro'];
$consultar->consulta($nota_venta);
the response JSON that i get is:
SELECT OHSNME,OHTOT$,OHREPÑ FROM DELLORTO.SANFPRD.FOMHDR WHERE OHORDÑ= 366
[{"OHSNME":"E.C. GM. ","OHTOT$":"1861.00",null:" A07"}]
you can see that OHORDÑ is probably the problem with the 'Ñ'
but this table are part a productive database and i can't update

Answer 1

Solution #1, alias the column name to a name without non-ascii characters:
$query=
"SELECT OHSNME,OHTOT$,OHREPÑ AS OHREPN
FROM MYDB.SANFPRD.FOMHDR
WHERE OHORDÑ= $parametro ";
Solution #2, manually serialize using utf8_encode():
$result=odbc_exec($this->conexion,$query);
while($row = odbc_fetch_object($result)){
$_row_fix = array();
foreach ($row as $field => $val) {
$_row_fix[utf8_encode($field)] = utf8_encode($val);
}
$datos[]= $_row_fix;
}