Retrieve data from database using PHP

Question

I am trying to retrieve data from mysql using PhP. I am just testing my PHP file. If this works then I will start working on getting those results to my Android App.

The PHP results shown are always null. I can confirm that data is available in the database.

DATABASE has table called:

population - Fields are: id, gender, city, state

The results are always:

{"success":1,"data":[{"id":null,"gender":null,"city":null,"state":null}]}

I am not sure what is wrong in the code:

 <?php
  include("db_config.php");

  $response = array();

  $gender = 'Male';

  // get a product from products table
  $result = mysql_query("SELECT * FROM population WHERE gender = '$gender'");

  if (!empty($result)) 
   {
    // check for empty result
    if (mysql_num_rows($result) > 0) 
     {

        $result = mysql_fetch_array($result);

        $data = array();

        $data ["id"] = $row["id"];
        $data ["gender"] = $row["gender"];
        $data ["city"] = $row["city"];
        $data ["state"] = $row["state"];

        // success
        $response["success"] = 1;

        $response["data"] = array();
        array_push($response["data"], $data);
        echo json_encode($response);
       }
    else 
     {
        $response["success"] = 0;
        $response["message"] = "No data found";

        echo json_encode($response);
     }
    }
  else 
   {

    $response["success"] = 0;
    $response["message"] = "No data found";
    echo json_encode($response);
     } 
  ?>

Can someone help me out with this php code? I have been working on this for last three days couldn't get any solution?

Thanks!

Have you tried like this... $result = mysql_query("SELECT * FROM population WHERE gender = '" . $gender . "'"); — Hiren Pandya
– Hiren Pandya, Commented Apr 10, 2013 at 11:25

Ranjith · Accepted Answer · 2013-04-10 11:23:09Z

2

Try it Now,

if (mysql_num_rows($result) > 0) 
     {

        $row = mysql_fetch_array($result);  // wrong initialize to the result value

        $data = array();

        $data ["id"] = $row["id"];
        $data ["gender"] = $row["gender"];
        $data ["city"] = $row["city"];
        $data ["state"] = $row["state"];
    }

answered Apr 10, 2013 at 11:23

Ranjith

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1 Comment

TheDevMan Over a year ago

$row was the issue. Changing it works great but why am I seeing only one result I should get three? Any idea on that?

Yogesh Suthar · Accepted Answer · 2013-04-10 14:15:28Z

1

change this

$result = mysql_fetch_array($result);

to

$row = mysql_fetch_array($result);

use below code to get the all data

while($row = mysql_fetch_array($result)) {
    $data = array();
    $data ["id"] = $row["id"];
    $data ["gender"] = $row["gender"];
    $data ["city"] = $row["city"];
    $data ["state"] = $row["state"];
    // success
    $response["success"] = 1;
    $response["data"][] = array();
    array_push($response["data"][], $data);
}
echo json_encode($response);

edited Apr 10, 2013 at 14:15

answered Apr 10, 2013 at 11:25

Yogesh Suthar

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3 Comments

DarkBee Over a year ago

mysql_fetch_array($res, MYSQL_ASSOC) *

TheDevMan Over a year ago

@Yogesh Suthar : $row was the issue. Changing it works great but why am I seeing only one result I should get three? Any idea on that?

Yogesh Suthar Over a year ago

@TheDevMan Because you didn't iterate the result with foreach OR while loop. See edited answer with while loop.....

Borniet · Accepted Answer · 2013-04-10 11:23:29Z

0

A variable in PHP is not evaluated when placed between single quotes.

"SELECT * FROM population WHERE gender = '$gender'"

Try concatenation:

$query = "SELECT * FROM population WHERE gender = '" . $gender "'";
mysql_query($query);

PS: Besides this error, I have to tell you it is best not to use mysql_* functions anymore, use mysqli or pdo!

answered Apr 10, 2013 at 11:23

Borniet

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4 Comments

Ranjith Over a year ago

Nope, This is not necessary to do this way of concatenate. Inside of double qouted ("") with single quote around ('$gender'). PHP parsing this value.

Borniet Over a year ago

@Ranjith do you have any reference to that? The rule of thumb is: between double quotes, vars expand, between single quotes, they don't. However, I tested, and it works as you say, but I can't find any documentation on that.

Ranjith Over a year ago

It's wrong. PHP doesn't parse the variable when around the single quotes like this '$gender'. But it can parse when like this way of assignment or execution " ........ '$gender' ......" . It's my humble request to you try a simple PHP program and check it out..

Borniet Over a year ago

Indeed, I tried it in a simple PHP prog, and noticed it does work. But indeed only when the single quotes are contained by double quotes.

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