using php to update records in mysql

Edit: Now that I actually found the time to test/look at your code, I noticed a few things.

Here is the update file.

<?php

    $conn = mysqli_connect ("localhost", "B00657633", "Jpr3EjPw")
        or die ("could not connect: " . mysqli_error($conn));
        print "successful connection<br>";

        mysqli_select_db($conn, 'B00657633') or die ('db will not open');



    $query = "UPDATE patient3 SET AGE=68 WHERE POST_CODE='bt667ed'";
    $result = mysqli_query($conn, $query) or die ("Query is invalid");

    $rownum = mysqli_affected_rows($conn);

    echo $rownum . " Records have been1 updated.";


    header('Location: sql5_2.php');

?>

Here is the sql5_2.php file.

<?php
$conn = mysqli_connect ("localhost", "B00657633", "Jpr3EjPw")
    or die ("could not connect: " . mysqli_error($conn));
    print "successful connection<br>";
        mysqli_select_db($conn, 'B00657633') or die ('db will not open');

    $query="SELECT * FROM patient3";
    $result = mysqli_query($conn, $query) or die ("Query is invalid");
    $num = mysqli_num_rows ($result);
    $col = mysqli_num_fields ($result);

    echo "<table border='2'><tr><th>PATNUM</th><th>PAT_FORENAME</th><th>PAT_SURNAME</th><th>STREET_ADDRESS</th><th>TOWN</th><th>POST_CODE</th><th>AGE</th>";
        for($j=0; $j<$num; $j++){
    $rows = mysqli_fetch_row($result);
    echo "<tr>";
    for($i=0; $i<$col; $i++){
        echo "<td>" . $rows[$i] . "</td>";
    }
    echo "</tr>";
}
echo "</table>";

echo " Records have been updated.";

mysqli_close($conn);
?>

In your code, you were doing a few things. First off, you were attempting to pass through the connection as a result set for the num_rows/num_fields methods. These are expecting the return values that actually contain data, like from a select query. The update query will return true or false, and how many rows it affected. So even after updating it to take the result variable, it was still attempting to pass through a boolean value to the methods.

You'll notice that I changed it to

mysqli_affected_rows()

which will check the number of rows affected for that mysqli_connect object that the query was executed through. From there, we can use that variable to output how many rows were affected.

Also, you were attempting to output the values of fields from an update query, which doesn't return the fields. Off of the top of my head, you would have to run a select query with the same parameters to get the set of data that will be changed, and then update that set. This way, you can use the set of data from the first select query to output which rows are being changed.

Keep in mind, that by using header('Location: ') you will redirect the user. So any output within the first file will not be seen as they are being sent to sql5_2.php.