😊

🙂

// change these settings
$servername = ‘localhost’;
$username = ‘dbuser’;
$password = ‘password’;
$db = ‘database’;

try {
// connect using PDO
$conn = new PDO(“mysql:host=$servername;dbname=$db”, $username, $password, [
PDO::MYSQL_ATTR_INIT_COMMAND => ‘SET sql_mode=”NO_ZERO_DATE”‘
]);
$conn->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
echo “Connected successfully\n”;

// get all table names
$stm = $conn->prepare(‘SHOW TABLES’);
$stm->execute();
$table_names = $stm->fetchAll(PDO::FETCH_COLUMN);

// for all tables
foreach ($table_names as $table_name) {
echo “\nRepairing table $table_name…\n”;

// get the primary key name
$stm = $conn->prepare(“SHOW KEYS FROM `$table_name` WHERE Key_name = ‘PRIMARY'”);
$stm->execute();
$primary_key_info = $stm->fetch(PDO::FETCH_ASSOC);
$key_name = $primary_key_info[‘Column_name’] ?? null;

if ($key_name) {
echo “Primary key is $key_name\n”;

// get the primary key type
$stm = $conn->prepare(“SHOW FIELDS FROM `$table_name` WHERE Field = ?”);
$stm->execute([$key_name]);
$key_type_info = $stm->fetch(PDO::FETCH_ASSOC);
$key_type = $key_type_info[‘Type’];

if ($key_type) {
try {
// if auto_increment was missing there might be a row with key=0 . compute the next available primary key
$sql = “SELECT (IFNULL(MAX(`$key_name`), 0) + 1) AS next_id FROM `$table_name`”;
$stm = $conn->prepare($sql);
echo “$sql\n”;
$stm->execute();
$next_id = $stm->fetch(PDO::FETCH_ASSOC)[‘next_id’];

// give a sane primary key to a row that has key = 0 if it exists
$sql = “UPDATE `$table_name` SET `$key_name` = $next_id WHERE `$key_name` = 0”;
echo “$sql\n”;
$stm = $conn->prepare($sql);
$stm->execute();

// set auto_increment to the primary key
$sql = “ALTER TABLE `$table_name` MODIFY COLUMN `$key_name` $key_type AUTO_INCREMENT”;
echo “$sql\n”;
$stm = $conn->prepare($sql);
$stm->execute();
} catch (PDOException $e) {
echo “\n\nQuery: $sql\nError: ” . $e->getMessage() . “\n\n”;
}
} else {
echo “No primary key type found for $key_name in table $table_name.\n”;
}
} else {
echo “No primary key found for table $table_name.\n”;
}
}

echo “\n\nFinished\n”;
} catch (PDOException $e) {
exit(“Connection failed: ” . $e->getMessage());
}

// close the connection
$conn = null;

‘SET sql_mode=”NO_ZERO_DATE”‘
]);
$conn->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
echo “Connected successfully\n”;

// get all table names
$stm = $conn->prepare(‘SHOW TABLES’);
$stm->execute();
$table_names = $stm->fetchAll(PDO::FETCH_COLUMN);

// for all tables
foreach ($table_names as $table_name) {
echo “\nRepairing table $table_name…\n”;

// get the primary key name
$stm = $conn->prepare(“SHOW KEYS FROM `$table_name` WHERE Key_name = ‘PRIMARY'”);
$stm->execute();
$primary_key_info = $stm->fetch(PDO::FETCH_ASSOC);
$key_name = $primary_key_info[‘Column_name’] ?? null;

if ($key_name) {
echo “Primary key is $key_name\n”;

// get the primary key type
$stm = $conn->prepare(“SHOW FIELDS FROM `$table_name` WHERE Field = ?”);
$stm->execute([$key_name]);
$key_type_info = $stm->fetch(PDO::FETCH_ASSOC);
$key_type = $key_type_info[‘Type’];

if ($key_type) {
try {
// if auto_increment was missing there might be a row with key=0 . compute the next available primary key
$sql = “SELECT (IFNULL(MAX(`$key_name`), 0) + 1) AS next_id FROM `$table_name`”;
$stm = $conn->prepare($sql);
echo “$sql\n”;
$stm->execute();
$next_id = $stm->fetch(PDO::FETCH_ASSOC)[‘next_id’];

// give a sane primary key to a row that has key = 0 if it exists
$sql = “UPDATE `$table_name` SET `$key_name` = $next_id WHERE `$key_name` = 0”;
echo “$sql\n”;
$stm = $conn->prepare($sql);
$stm->execute();

// set auto_increment to the primary key
$sql = “ALTER TABLE `$table_name` MODIFY COLUMN `$key_name` $key_type AUTO_INCREMENT”;
echo “$sql\n”;
$stm = $conn->prepare($sql);
$stm->execute();
} catch (PDOException $e) {
echo “\n\nQuery: $sql\nError: ” . $e->getMessage() . “\n\n”;
}
} else {
echo “No primary key type found for $key_name in table $table_name.\n”;
}
} else {
echo “No primary key found for table $table_name.\n”;
}
}

echo “\n\nFinished\n”;
} catch (PDOException $e) {
exit(“Connection failed: ” . $e->getMessage());
}

// close the connection
$conn = null;

Thank you for the additional info, glad you got it working!

[04-Oct-2020 19:42:21 UTC] WordPress database error Duplicate entry ‘0’ for key ‘PRIMARY’ for query INSERT INTO `wp4jf_usermeta` (`user_id`, `meta_key`, `meta_value`) VALUES (1, ‘session_tokens’, ‘a:1:{s:64:\”9baffd8837197c7ddb22d813a8465ee1a…

I saw this and solution was in front of my eyes, but googling took me to your website and first sentence opened my eyes! I am sure thousands of developers are going nuts over the fact they are just getting login page refreshed after trying to log in! Never happened before with AUTOINCREMENT after migrating, strange!
Anyway, thak you very much, life saving info. I did it manually, since I had many double IDs, especially in “yourprefix_options” table. So – for some of you guys: phpmyadmin and go through it one by one, or if you’re lucky use Alex’s script!

Very glad that the article helped you!

And thank you for your very kind words!