[BUG] MySQL helpers are wrong with duplicate table names in different schemas

[isseii10]

Hi.
I found a bug when tables with the same name exist in different schemas.

Reproduction Example:

CREATE DATABASE db1;
CREATE DATABASE db2;

CREATE TABLE db1.users (
  id int,
  name varchar(255)
);

CREATE TABLE db2.users (
  id int,
  name varchar(255)
);

INSERT INTO db1.users VALUES (1, "db1user");
INSERT INTO db2.users VALUES (1, "db2user");

ALTER TABLE db1.users ADD INDEX idx_name_db1 (name);
ALTER TABLE db2.users ADD INDEX idx_name_db2 (name);

When connected to db1, selecting 'List', 'Columns', or 'Indexes' for db2.users shows the result for db1.users instead.

[isseii10]

I have identified the cause of the bug and created a PR.
I would appreciate it if you could take a look!

#164