To access the Odoo 15 database tables using queries, you can use the pgAdmin tool (if you are using the PostgreSQL database) or the MySQL Workbench (if you are using the MySQL database).

Here are the steps to access the Odoo 15 database tables using pgAdmin:

1. Open pgAdmin and connect to your Odoo 15 database.

2. Right-click on the database name and select "New Query".

3. In the query editor, enter your SQL query and run it by clicking on the "Execute" button or by pressing the F5 key.

4. The query will return the data from the selected table.

Here are the steps to access the Odoo 15 database tables using MySQL Workbench:

1. Open MySQL Workbench and connect to your Odoo 15 database.

2. Click on the "SCHEMAS" tab to see the list of all the databases in your system.

3. Click on the database you want to access and then click on the "SQL" button on the top menu to open the SQL editor.

4. In the SQL editor, enter your SQL query and run it by clicking on the "Execute" button or by pressing the F5 key.

5. The query will return the data from the selected table.

It's important to note that, to avoid errors, you have to have the proper credentials to access the database and the proper understanding of the database structure, the sql language and the security policies of the company.

You can also use the Odoo ORM api that is built on top of the database to access the data in a more user-friendly and safe way.

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