chore: add resource under postgresql-dba:rdbms-concepts:object-model:queries

src/data/roadmaps/postgresql-dba/content/102-rdbms-concepts/100-object-model/106-queries.md

@@ -84,4 +84,6 @@ FROM users
 WHERE id IN (SELECT DISTINCT user_id FROM orders);
 ```
 
-There's much more to explore with various types of queries, but this foundational knowledge will serve as a solid basis for further learning and experimentation.
+There's much more to explore with various types of queries, but this foundational knowledge will serve as a solid basis for further learning and experimentation.
+
+- [Querying a Table](https://www.postgresql.org/docs/current/tutorial-select.html)