MySQL query variable not accepted

Question

I am working on a PHP script that should get data from MySQL.

Here is what am I doing:

<?php
include('db.php');
session_start();
$doctor_actual=$_SESSION['doctor_actual'];
echo $doctor_actual;
 if(isset($_REQUEST['actionfunction']) && $_REQUEST['actionfunction']!=''){
$actionfunction = $_REQUEST['actionfunction'];

   call_user_func($actionfunction,$_REQUEST,$con,$limit,$adjacent);
}
function showData($data,$con,$limit,$adjacent){
  $page = $data['page'];
   if($page==1){
   $start = 0;  
  }
  else{
  $start = ($page-1)*$limit;
  }
  $sql = "select * from tb_opiniones_doctor where codigo_verificacion = '".$doctor_actual."' order by id_opinion_doctor asc";
  $rows  = $con->query($sql);
  $rows  = $rows->num_rows;

  $sql = "select * from tb_opiniones_doctor where codigo_verificacion = '".$doctor_actual."'  order by id_opinion_doctor asc limit $start,$limit";

  $data = $con->query($sql);
  $str='<table><tr class="head"><td>Id</td><td>Firstname</td><td>Lastname</td></tr>';
  if($data->num_rows>0){
   while( $row = $data->fetch_array(MYSQLI_ASSOC)){
      $str.="<tr><td>".$row['id_opinion_doctor']."</td><td>".$row['id_opinion_doctor']."</td><td>".$row['id_opinion_doctor']."</td></tr>";
   }
   }else{
    $str .= "<td colspan='5'>No Data Available</td>";
   }
   $str.='</table>';

echo $str; 
pagination($limit,$adjacent,$rows,$page);  
}

My problems are at the two queries, they only work if I put the real value for $doctor_actual, not as variable.

I have echoed the value for $doctor_actual, it is 9dv2ACvtwn2.

If I put in the queries ..where codigo_verificacion = "9dv2ACvtwn2"... the queries work fine.

If I put:

codigo_verificacion = '".$doctor_actual."'

or

codigo_verificacion = '.$doctor_actual.'

or

codigo_verificacion = $doctor_actual

it shows the message:

No Data Available

Wolen · Accepted Answer · 2017-02-26 20:13:22Z

3

You should read about Variable scope. $doctor_actual outside function and $doctor_actual inside function are two different variables. As you can read above something like that

<?php
$var = 'text';

function myFunc()
{
   global $var;
   echo $var; // 'text'
}

will solve your problem.

But as noticed @Sean in comments below it's better idea to pass value as a parameter. Just add additional parameter to your function and pass value during function call.

edited Feb 26, 2017 at 20:13

answered Feb 26, 2017 at 20:00

Wolen

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3 Comments

Sean Over a year ago

Although technically correct, it is typically not encouraged to recommend using global -> global $var;. As they are already using function parameters, why not recommend that that add it there.

Wolen Over a year ago

You're right, pass value as a parameter is better idea, I'll update my answer, thanks!

mvasco Over a year ago

Thank you both, I have added $doctor_actual as parameter to the function and works fine.

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