Why does an error occur when creating a table?

Question

MySQL

tell me what's wrong?
CREATE TABLE pass_old ( 'userid' INT(11) NOT NULL AUTO_INCREMENT, 'pass_old' varchar(256), FOREIGN KEY ('userid') REFERENCES users('userid') on delete cascade);
ERROR 1064 (42000): You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near ''userid' INT(11) NOT NULL AUTO_INCREMENT, 'pass_old' varchar(256), FOREIGN KEY (' at line 1

Answer 1

Because straight quotes (') denote a string, backticks (`) are used to denote table and field names.