getting duplicated results from nested foreach loop - php

Question

I'm trying to get the following output from mysql for Google Line Chart API:
[["product","diameter","width"],["Product 1","2","4"],["Product 2","4","8"]]
I have set up several input checkboxes to send field names (e.g width,diameter) to the database via $_POST["info"] and retrieve the values from those fields. Here's the part that generates the data from mysql:
$result = $users->fetchAll();
$comma = "";
$data="";
$data[0] = array_merge(array(product),$info);
$i = 1;
foreach ($result as $r)
{
foreach($_POST["info"] as $p)
{
$d .= $comma.$r[$p]; // trying to get "$r["width"],$r["diameter"]"
}
$comma = ",";
$data[$i] = array($r["name"], $d);
$i++;
}
echo json_encode($data);
My desired output should be like this:
[["product","diameter","width"],["Product 1","2","4"],["Product 2","4","8"]]
But that code is generating duplicated results like this
[["product","diameter","width"],["Product 1","24"],["Product 2","24,4,8"]]
I guess I shouldn't be using the nested foreach to loop over $_POST. Can anyone tell me how to fix that?
Full PHP Code:
$info = $_POST["info"]; // It contains an array with values like width,diameter,thickness etc...
$comma = "";
foreach($info as $in)
{
$field .= "".$comma."b.".$in."";
$comma = ",";
}
$sql = "
SELECT {$field},a.user_id,a.name
FROM `product_detail` a INNER JOIN
`attr` b ON a.model = b.model
WHERE a.user_id = ?
GROUP BY a.model
";
$users = $dbh->prepare($sql);
$users->bindValue(1, $_SESSION["user_id"]);
$users->execute();
$result = $users->fetchAll();
$comma = "";
$data="";
$i = 1;
$data[0] = array_merge(array(product),$info);
foreach ($result as $r)
{
foreach($_POST["info"] as $p)
{
$d .= $comma.$r[$p];
}
$comma = ",";
$data[$i] = array($r["name"], $d);
$i++;
}
echo json_encode($data);
$_POST["info"] Content:
Array
(
[0] => diameter
[1] => width
)

Answer 1

try it like this:
$result = $users->fetchAll();
$data="";
$data[0] = array_merge(array(product),$info);
$i = 1;
foreach ($result as $r)
{
$d[]=$r["name"];
foreach($_POST["info"] as $p)
{
$d[]= $r[$p];
}
$data[$i] = $d;
$d=array(); //set $d to empty not to get duplicate results
$i++;
}
echo json_encode($data);

Answer 2

The end result you are looking for, is valid JSON. You should not try to manually generate that.
Instead you should make an array of arrays in php and use json_encode($array) to get the result you are looking for.
Also note that by injecting your POST variables directly in your query, you are vulnerable to sql injection. When accepting fields, you should check them against a white-list of allowed values.

Answer 3

Try the below solution:
$result = $users->fetchAll();
$data="";
$data[0] = array_merge(array(product),$info);
$i = 1;
foreach ($result as $r)
{
$d = array();
foreach($_POST["info"] as $p)
{
$d[] = $r[$p]; // trying to get "$r["width"],$r["diameter"]"
}
$data[$i] = array($r["name"]) +$d;
$i++;
}
echo json_encode($data);