如何附加到现有列PHP中的字段

Question

Sorry about the title of the question, I don't quite know how to ask what I am trying to accomplish here. Perhaps my code samples below can be more of help to you. But first here is a little information.

I am using the PDO driver to execute queries to my database.

$stmt = $this->conn->prepare("UPDATE `support` SET `message` = `message` + :message WHERE `id` = :id AND `userid` = :uid");
$stmt->bindParam(':id', $id, PDO::PARAM_INT);
$stmt->bindParam(':uid', $userid, PDO::PARAM_INT);
$stmt->bindParam(':message', $smessage, PDO::PARAM_STR);
if ($stmt->execute()) {
    $this->formatted_message($userid);
}

Answer 1

The plus sign is only for numbers in sql.

Mysql offers the function concat instead.

Your query would become:

UPDATE `support` SET `message` = concat(`message`, :message) WHERE `id` = :id AND `userid` = :uid