Error with WordPress query using $wpdb get_results [duplicate] - php

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Fatal error: Uncaught Error: Call to undefined function mysql_connect()
(9 answers)
Closed 4 years ago.
I have added a post in my WordPress database with the title "titleofpost". I try to use in PHP 7 $wpdb get_results, but I get the following error:
Fatal error: Uncaught Error: Call to undefined function mysql_error().
What is wrong? Any help is appreciated.
I use the code below:
global $wpdb;
$leadTitle="titleofpost";
$sql = "SELECT * FROM $wpdb->posts WHERE post_title LIKE '%$leadTitle%'";
$post_if = $wpdb->get_results($sql) or die(mysql_error()); //here dies

Answer 1

thy this
global $wpdb;
$leadTitle="titleofpost";
$sql = "SELECT * FROM $wpdb->posts WHERE post_title LIKE '%$leadTitle%'";
$post_if = $wpdb->get_results($sql) or die(mysqli_error()); //here dies
mysql_* functions have been removed in PHP 7.
You probably have PHP 7 in XAMPP. You now have two alternatives: MySQLi and PDO.
Additionally, here is a nice wiki page about PDO.
Handling errors with PDO
PDO has multiple ways of handling errors.
There are three error modes for PDO.
The first is PDO::ERRMODE_SILENT. This acts much like the mysql_* functions in that after calling a PDO method you need to check PDO::errorCode or PDO::errorInfo to see if it was successful.
The second error mode is PDO::ERRMODE_WARNING. This is much the same except an E_WARNING message is also thrown.
The final error mode is PDO::ERRMODE_EXCEPTION. This one throws a PDOException when an error occurs. This is the method I recommend and will be using it for further examples.
// You can set the error mode using the fourth options parameter on the constructor
$dbh = new PDO($dsn, $user, $password, array(PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION));
// or you can use the setAttribute method to set the error mode on an existing connection
$dbh->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
//METHOD 2
try {
$dbh = new PDO($dsn, $user, $password, array(PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION));
} catch (PDOException $e) {
log_error("Failed to connect to database", $e->getMessage(), $e->getCode(), array('exception' => $e));
}
//METHOD 3
try {
$dbh->query("INVALID SQL");
} catch (PDOException $e) {
log_error("Failed to run query", $e->getMessage(), $e->getCode(), array('exception' => $e));
}

Answer 2

According to this, then mysql_error() is deprecated since PHP 5.5.0. Perhaps try error_log() instead (and then look in the php error log).
It's probably this part of your code that causes the error: or die(mysql_error());