Selecting table data with PDO statements [duplicate] - php

Question

This question already has answers here:
How can I use PDO to fetch a results array in PHP?
(2 answers)
Closed 2 years ago.
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>" . $row['id'] . "</td>";
echo "<td>" .$row['anum'] . " </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!

Answer 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.

Answer 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.