MySQL next and prev record issue - php

Question

I made this php script and i am tryin to make it to return next and previus row, but there is one problem when i input my id the script return different thing for example :
This is my DB
ID String
1 Test 1
2 Test 2
3 Test 3
4 Test 4
So if i put ./index.php?id=1 this returns the result of id=2 and id=2 => id=3 and so on...
My question is how to fix it to return accurate result not +1. I tried with <= or => operators the result is correct, but then my links doesnt work.
Here is the script
<?php
if(isset($_GET['id']))
{
$id = (int)$_GET['id'];
}else
{
$id = 0;
}
$stmt1 = $db->prepare("SELECT * FROM records WHERE id > ? ORDER BY id ASC LIMIT 1");
$stmt1->bindValue(1,$id);
$stmt1->execute();
$row = $stmt1->fetch();
$stmt2 = $db->prepare("SELECT * FROM records WHERE id < ? ORDER BY id DESC LIMIT 1");
$stmt2->bindValue(1,$id);
$stmt2->execute();
$row = $stmt2->fetch();
echo $row['id'];
echo "<br/>";
echo $row['string'];
?>

Answer 1

I am not sure if the problem as silly as that, but I have no other explanation.
To have your page you need to make 3 selects:
to get current page data
to get prev id
to get next one
But I can see only 2 selects
So, you have to select data for the very page to show
if(isset($_GET['id']))
{
$sql = "SELECT * FROM records WHERE id = ?";
$stm = $db->prepare($sql);
$stm->execute(array($_GET['id']));
} else {
$sql = "SELECT * FROM records ORDER BY id ASC LIMIT 1";
$stm = $db->query($sql);
}
$row = $stm->fetch();
and now you can go for getting prev and next ids
$sql = "SELECT id FROM records WHERE id < ? LIMIT 1";
$stm = $db->prepare($sql);
$stm->execute(array($row['id']));
$prev = $stm->fetchColumn();
$sql = "SELECT id FROM records WHERE id > ? LIMIT 1";
$stm = $db->prepare($sql);
$stm->execute(array($row['id']));
$next = $stm->fetchColumn();

Answer 2

i am tryin to make it to return next and previus row
There is no such thing as "previous" or "next" row in a table. Without explicit ordering, tables must be considered as unordered set of rows. And you shouldn't rely on auto_increment field to be sequentially numbered. For example:
because there was interleaved insert on the table,
because the server is allowed to reuse auto_increment after row deletion.
You probably have to modify your table structure to add a sequence number:
CREATE TABLE tbl (id in primary key not null auto_increment,
sequence_number int unique,
value char(40));
While inserting your data you might rely on something like that:
INSERT INTO tbl (sequence_number, value)
VALUES (SELECT COUNT(*) FROM tbl, ?)
And the query for the "next" and "prev":
SELECT * FROM tbl WHERE sequence_number = ?-1 OR sequence_number = ?+1
ORDER BY sequence_number;