PDO Connection error vs SQL Error, how to detect - php

Question

I regularly send copies of WordPress data to a more structure in a Cloud SQL Database (a single woo order in a single row instead of multiple tables) for the benefits of reporting and backups etc.
Im now creating a component that will write the same data to a local copy of the Cloud DB in case there is a network error as a backup which can then be inserted at a later date once the connection is restored.
Im trying to distinguish the difference between a connection error and an SQL error. If I have a connection error then I can use the local copy, if there is an SQL error then I can write the error to a log file as the statement wouldn't work anyway.
Here is my code:
<?php
try {
//Connect to the DB
$connection = new PDO("mysql:host=$this->servername;dbname=$this->database",$this->u,$this->p,[
PDO::MYSQL_ATTR_SSL_KEY => $this->ck,
PDO::MYSQL_ATTR_SSL_CERT => $this->cc,
PDO::MYSQL_ATTR_SSL_CA => $this->sc,
PDO::MYSQL_ATTR_SSL_VERIFY_SERVER_CERT => false
]
);
$connection->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
$statement = 'INSERT BLA BLA BLA';
$statement->execute();
}
//Log any errors. However, at this point I would like to drill down into the error to find out if its a connection error or an sql error!
catch(PDOException $e) {
//DcgsqlErrorLog(Object name, Object ID, PDO Error message))
new DcgsqlErrorLog('Product',$this->product->get_id(),$e->getMessage());
}
//Close connection and return
finally {
$connection = null;
return;
}
?>