在 mySQL 中插入带有特殊字符的 JSON 编码值失败

Question

I am trying to execute this query with PDO:

UPDATE categories
SET keywords = '{"bg":["keyword1","\u0431\u044a\u043b\u0433\u0430\u0440\u0441\u043a\u0438 "]}'
WHERE id = 4;

The problem is that it seems to record the hex value without the backslashes ("\\"). It does show up without the backslashes in my app but also in PHPMyAdmin.

I use exec() on this query, and I have tried it with this full-text query, without any dynamic/transformed variables. The PDO parameters are as follow:

PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION,
PDO::MYSQL_ATTR_USE_BUFFERED_QUERY => true,
PDO::MYSQL_ATTR_INIT_COMMAND => "SET NAMES utf8"

Can someone explain me what is happening here? Thanks!

UPDATE: I have executed this exact query from mysql's CLI, then displayed it there, and the problem is the same: all the backslashes have disappeared. So it doesn't seem the problem has anything to do with PDO, but with MySQL - or me! My version is 5.1.53

Answer 1

The \\ character has special meaning in SQL. Use bound parameters instead of hardcoding the value into the base string you use for the query.