how to fetch the data from the database using for loop using php from mysql?

Question

i am trying to fetch the data from the database using the for loop format but the loop is execute but but the data cannot be retrived.

this is my php code

  $resultss = array_unique($Employeeids);
              // echo sizeof($resultss);


            for($i = 0; $i<=sizeof( $resultss); $i++) 
                {
                     //echo $resultss[$i]. "<br>";

                     if($resultss[$i] !='')
                     {

                         $uniqueemp_id[$i]=$resultss[$i];
                         echo $uniqueemp_id[$i]."hi". "<br>";

                        $sql[$i]="Select Token From user Where Employeeid= '".$uniqueemp_id[$i]."'";

                            $result[$i]=mysqli_query($con,$sql[$i]);
                            echo $sql[$i];//upto here loop is executing correctly but while is not executing.
                                 while($row = mysqli_fetch_assoc($result[$i]))
                                    {
                                        echo $tokens =  $row['Token']. "<br>";          
                                    }


                    mysqli_close($con);

                     }
                }

echo screen

i can able to fetch and display the token of employee id 9 but not able to display the token of employee id 15 ,i cannot able to find what is the error can anyone help me to fix this issue!

Answer 1

Your core issue is that you close the connection ( mysqli_close ) at the end of the first iteration. Move that to at least outside and below your loop.

EDIT

There are a number of chances for code improvement here. I was going to ignore them, until I saw the lack of prepared statements. In assorted order.

1. At least in the snippet provided, there is no need for $i . Just use foreach, and cleanup the ensuing references to $i :

    foreach ( $resultss as $empId ) {

2. Styling wise, save yourself some indentation with continue . Rather than

   if($empId != '') { ...

   use:

    if ( ! $empId ) continue; ...

3. Unless you need $uniqueemp_id later, just don't use it at all. Stick with $empId

4. In general, get in the habit of using prepared statements with bound parameters. It's a security thing, it's a performance thing, it's a simplicity thing, it's good habit. Just do it.

   Prepare a single query, and execute it multiple times, or get all of the results with the IN SQL operator. A single prepared query executed multiple times:

    $sql = 'SELECT token FROM user WHERE employeeid = ?'; $sth = mysqli_prepare($con, $sql); # "statement handle" if ( ! $sth ) die('Unable to create prepared statement'); foreach ( $resultss as $empId ) { ... mysqli_stmt_bind_param($sth, "s", $empId); mysqli_stmt_execute( $sth ); $result = $sth->get_result(); while ($row = $result->fetch_assoc()) echo "Token: {$row['token']}<br>"; }

   I'll leave the IN operator as an "exercise to the reader".