Selecting table data with PDO statements

Question

I have a php script that selects data via mysql_, however recently I have been reading that PDO is the way to go and that mysql_ is becoming depreciated. Now I am converting that script to PDO.

My question is though, I am not using $_POST to select. I just want to select the entire table with all of its data so I enter this query :

$query = $dbh->prepare("SELECT * FROM students");
$query->execute();
$result = $query->fetchall(); // or you can just $result = $query as hakre proposed!

so then like I did with my old depreciated mysql_ version of the script I used the echo to echo a table with the data in it.

    echo 
    "<table border='2'>
    <tr>
    <th>ID</th>
    <th>A Number</th>
    <th>First Name</th>
    <th>Last Name</th>
    <th>Why</th>
    <th>Comments</th>
    <th>Signintime</th>
    </tr>"
    ;

    foreach($result as $row)
    {
  echo "<tr>";
  echo "<td>" . $row['id'] . "</td>";
  echo "<td><a href=Student.php?studentA_num=" . $row['anum'] . ">" .$row['anum'] . " </a></td>";
  echo "<td>" . $row['first'] . "</td>";
  echo "<td>" . $row['last'] . "</td>";
  echo "<td>" . $row['why'] . "</td>";  
  echo "<td>" . $row['comments'] . "</td>";
  echo "<td>" . $row['signintime'] . "</td>";
  echo "<td> <input type=\"button\" value=\"Start Session\"onClick=\accept.php?id=" . $row['id'] . "&start=true></td>";
}

  echo "</tr>";
  echo "</table>";

now using this, I can not get a single output to my table.

My question is am I missing something from my select statements? Or am I not fetching any rows? Also I the connection settings set in another script called connect.php that is required by init.php (at the top of all of my pages)

Edit : 1

Edited the code so it now works, also adding a picture to show others how it should look! Hopefully some one can put this to some sort of use!

Solution 1

You are doing too much actually:

$query = $dbh->prepare("SELECT * FROM students");
$query->execute();
$result = $dbh->query($query);

The problematic line is:

$result = $dbh->query($query);

Check with http://php.net/pdo.query, the parameter is a string, actually the SQL string you already use above, not the result value of a PDO::prepare() call.

For your simple query you can just do:

$result = $dbh->query("SELECT * FROM students");

Or if you like to prepare:

$query = $dbh->prepare("SELECT * FROM students");
$query->execute();
$result = $query;

The later is some boilerplate if you want to insert variables into the query, that's why you prepare it.

---

The next problem is with the foreach line:

foreach($result as $row);

You are terminating the loop immediately because of the semicolon ; at the end. Remove that semicolon so that the following angle-bracketed code-block becomes the body of the foreach-loop.

Solution 2

Your code is wrong:

$query = $dbh->prepare("SELECT * FROM students");
$query->execute();
$result = $dbh->query($query);

After executing a prepared statement, you can just call fetchAll() on it:

$query = $dbh->prepare("SELECT * FROM students");
$query->execute();
$result = $query->fetchAll();

The rest of your code will work fine once you remove the semicolon after the foreach.

Comments

[RaGe10940]

such a foolish mistake on my part! Thank you to the both of you guys!

[hakre]

You are new. In case you run into a problem, start to verify from top to bottom. You can look into variables with var_dump(), often helpful. Also set your error reporting for development to on and to the highest level.