store the local time of the client in mysql table - php

Question

I am trying to store the local time zone of the client on the hosting home page ut I am getting this error in my android Logcat You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '' at line 7 How can I do that? I tried it with date_default_timezone_set
I appreaciate any help.
<?php
$data = json_decode ( file_get_contents ( 'php://input', true ) );
$mac = $data->{'mac'};
$latitude = $data->{'latitude'};
$longitude = $data->{'longitude'};
$route = $data->{'route'};
$created_at = date_default_timezone_set("Europe/Berlin");
$con = new mysqli ( "domin.com", "username", "password", "ddatabase" );
// check whether route's table exist.
$results = $con->query ( "SHOW TABLES like 'bus' " ) or die ( mysqli_error () );
if (($results->num_rows) == 1) {$sql = "REPLACE INTO bus(mac, route, latitude, longitude, created_at)
VALUES( ?, ?, ? , ?, ? )";
$stmt = $con->prepare($sql);
if(false === $stmt){
echo "prepare() failed: ";
}
$rc = $stmt->bind_param("sssss",$mac,$route, $latitude,$longitude, $created_at );
echo $rc;
if ( false===$rc ) {
echo "bind_param() failed: ";
}
$rc = $stmt->execute();
if ( false===$rc ) {
echo "execute failed.";
}
$stmt->close();
} else {
$create = "CREATE TABLE bus
(id INT(11) NOT NULL AUTO_INCREMENT PRIMARY KEY,
mac VARCHAR(30) NOT NULL UNIQUE,
route int(11) ,
latitude FLOAT(10,6) NOT NULL ,
longitude FLOAT(10,6) NOT NULL,
created_at TIMESTAMP NOT NULL" ;
$stmt = $con->prepare($create) or die ( $con->error );
$stmt->execute();
$stmt->close();
}

Answer 1

date_default_timezone_set returns a bool, not a date. You can use date without specifying a timestamp parameter to get the current client time. Make sure that the format of the date matches what your table expects.