Vfrdtyky

I have an array of ID's used to execute mysqli queries in a foreach loop (the below code is just an example - the array will contain more than 50+ elements/ID's). For each array element/ID I query an array which I then include in a compData array. However, I am unsure of how to dynamically define the arrays in the foreach loop. I would very much appreciate if you can check whether I am using ${$val} correctly in the below or if something else is wrong. Thanks.

  $idArray  = array(

    "List1",

    "List2",

  );



  $compData = array();

  foreach($idArray as $val) {

    $sth = mysqli_query($conn, "SELECT * FROM {$tableName} WHERE ID = {$val}");

    ${$val} = array();

    while($r = mysqli_fetch_array($sth)) {

      For ($n = 1; $n <= $CI_NOYEARS; $n++){

        ${$val}['data'] = $r[$n]; 

      }

    }

    $compData[{$val}] = ${$val}

  }



  foreach($compData['List1'] as $result) {

    For ($n = 0; $n <= $CI_NOYEARS; $n++){

      echo $result[$n];

    }

  }

The above code does not work and does not echo any data from the $compData array. Below is an example that works just fine where I execute the code using the ID's directly.

  $sth = mysqli_query($conn, "SELECT * FROM {$tableName} WHERE ID = 'List1'");

  $List1 = array();

  while($r = mysqli_fetch_array($sth)) {

    For ($n = 1; $n <= $CI_NOYEARS; $n++){

        $List1['data'] = $r[$n];

    }

  }



  $companyData = array();

  $companyData['List1'] = $List1;



  foreach($compData['List1'] as $result) {

    For ($n = 0; $n <= $CI_NOYEARS; $n++){

      echo $result[$n];

    }

  }

It's a bit tough figuring out what your goal is based on the code you provided, but it seems far more complicated than it needs to be. I think what I've got here will replicate your desired output.

You should also be using prepared statements; they are safer, and take a lot of the overhead out of database queries when you're going to be repeating the same query multiple times. I've implemented them here.

$idArray = ["List1", "List2"];

$sth     = $conn->prepare("SELECT * FROM `$tableName` WHERE ID = ?");



foreach($idArray as $val) {

    $data = ;

    $sth->bind_param("s", $val);

    $sth->execute();

    $result = $sth->get_result();

    while ($r = $result->fetch_array()) {

        $data = array_merge($data, array_splice($r, 1, $CI_NOYEARS));

    }

    $compData[$val]["data"] = $data;

}



foreach($compData["List1"]["data"] as $result) {

    echo $result;

}

I don't understand why you're using that curly-brace notation at all when you're just copying it over into a multidimensional compData array anyway? Why not just directly put the data into the array:

for ($n = 1; $n <= $CI_NOYEARS; $n++) {

    $compdata[$val]['data'] = $r[$n];

}

(You'll also need to declare it as an array at the top level of the foreach of course.)

Side note: I would suggest not interpolating data directly into your query string like that, and instead using bound parameters: http://php.net/manual/en/mysqli-stmt.bind-param.php It's much more secure.