Mysql select into PHP associative array not working

Question

I was trying to get the response from an SQL select statement but when I try to echo the array encoded to JSON I don't have anything written except the "-" I echo to ensure myself that is entering into the loop.

$sql = "SELECT * FROM PREGUNTA WHERE PREGUNTA.pregunta LIKE '%$palabra_clave%' OR PREGUNTA.respuesta_correcta LIKE '%$palabra_clave%' OR PREGUNTA.respuesta_falsa_1 LIKE '%$palabra_clave%' OR PREGUNTA.respuesta_falsa_2 LIKE '%$palabra_clave%' OR PREGUNTA.retroalimentacion LIKE '%$palabra_clave%'";
$query = mysqli_query($con, $sql);

$json = array();

while($data = $query->fetch_assoc()){
  $json[] = array(
      'pregunta' => $data['pregunta'],
      'respuesta_correcta' => $data['respuesta_correcta'],
      'respuesta_falsa_1' => $data['respuesta_falsa_1'],
      'respuesta_falsa_2' => $data['respuesta_falsa_2'],
      'retroalimentacion' => $data['retroalimentacion']
  );

    echo $data['pregunta'];
    echo '<br>';
}

echo json_encode($json);

And I this is my output:

¿Cuál no es un lenguaje de programación web?
¿Cuál es el lenguaje web más importante?

Have you checked your error logs? You're making an assumption the query is working. — Jay Blanchard, Mar 15 '16 at 12:16
@Jay Blanchard 5 I have cheked the error logs and I don't have any error about the query. Also if the query wouldn't be well written it wouldn't enter in the loop I think. — Juan Manuel Amoros, Mar 15 '16 at 12:27
The query is the only explanation. How many times is the `-` echoed? Once? Definitely the query. — Jay Blanchard, Mar 15 '16 at 12:28
Add some error checking in your script - there are lots of scenarios where nothing will be written to mysql's error log, and nothing here which writes to the webserver error log. — symcbean, Mar 15 '16 at 12:37
@JayBlanchard Actually I edited my post so to see if I'm getting good results from my query and the query seems to work fine. I changed the "-" to echo the db information. It seems that the array is the problem but certainly I am not completely sure. — Juan Manuel Amoros, Mar 15 '16 at 12:44
Add error reporting to the top of your file(s) right after your opening ` — Jay Blanchard, Mar 15 '16 at 12:46
Also, make sure you have PECL json installed. Maybe test something you know works like `echo json_encode(array('message' => 'test'));` — toomanyredirects, Mar 15 '16 at 12:47
@JayBlanchard I added the lines to the top of my file but the result is the same, I don't get any error/warning printed. — Juan Manuel Amoros, Mar 15 '16 at 12:52
@toomanyredirects if I echo $json["pregunta"]; it shows me the information of the array so the only problem I think it could be is the json_encode — Juan Manuel Amoros, Mar 15 '16 at 13:02
@toomanyredirects and if I write echo json_encode($json["pregunta"]); it prints me nothing. — Juan Manuel Amoros, Mar 15 '16 at 13:04
Add as last line `echo json_last_error_msg();` and tell us what you get. — trincot, Mar 15 '16 at 13:37

score 3 · Accepted Answer · answered Mar 15 '16 at 13:33

3

Most likely your input does not use the UTF-8 character encoding. According to the documentation for json_encode "All string data must be UTF-8 encoded".

When I pass an array containing "¿Cuál no es un lenguaje de programación web?" to json_encode, it works fine. But if I first convert the text to ISO-8859-1, json_encode returns boolean false and therefore outputs nothing.

Assign your variables to the array with (eg):

$json[] = array('pregunta' =>
    mb_convert_encoding($data['respuesta_correcta'], 'UTF-8', 'ISO-8859-1'),
    // ...
);

or convert your database and application to use UTF-8 to start with.

answered Mar 15 '16 at 13:33

Matt Raines

4,149
8
31
34

That was the problem. Now it works really good converting the encoding, but the server conection is in UTF8_general_ci, the database is in UTF8-spanish_ci and the tables are in UTF8-spanish_ci. Do you have any idea why I am having this problem? – Juan Manuel Amoros Mar 15 '16 at 15:18
Have a browse through [UTF-8 all the way through](http://stackoverflow.com/questions/279170/utf-8-all-the-way-through). Chances are something in your stack isn't configured to use UTF-8 correctly. – Matt Raines Mar 15 '16 at 15:22

Mysql select into PHP associative array not working

1 Answers1