Is PDO prepared statements 100% safe against SQL injection in PHP?

Prepared statements protect you against 99.9% of injection vectors for data values, but there are 3 critical caveats:

1. Identifiers cannot be parameterized: You cannot bind table names, column names, or ASC/DESC keywords. For dynamic columns, always use a strict whitelist:
= ['created', 'likes', 'views']; = in_array(, ) ? : 'created';
2. Emulated prepares & Charset: Make sure PDO::ATTR_EMULATE_PREPARES => false is disabled and always set charset=utf8mb4 in your DSN string.
3. LIMIT clauses in older MySQL versions can sometimes misbehave if PDO sends them as strings instead of integers. Use PDO::PARAM_INT explicitly.

Spot on about ATTR_EMULATE_PREPARES. If emulation is on, PDO simulates prepares on the client side instead of using native database engine statement prepares. Disabling emulation is step #1 on any new project.