OcurriĆ³ un Error con la Base de Datos

Error Number: 1064

You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near '' at line 1

select titulo from productos_categorias where id=

Filename: /var/www/vhosts/generaldietetica.com/httpdocs/models/consultas.php

Line Number: 1242