In this chapter, you learned how to use advanced querying techniques. First, you learned how to use subqueries, which includes non-correlated subqueries and how to use each with the SELECT, FROM, and WHERE clauses, and also how to use them in INSERT, UPDATE, and DELETE queries. You also learned about correlated subqueries and how to use them with the SELECT, FROM, and WHERE clauses.

Next, you learned about the different kinds of CTEs and how to use them, including recursive and non-recursive. Then, you learned about query hints and how to choose which index your query will use. Finally, you learned about isolation levels, which include four levels and what happens during each level. You also learned how to set your queries to use a specific isolation level. 

In the next chapter, you will learn how to create programmable objects. By the end of the next chapter, you will be able to understand what types of views exist and how to use them, as well as when and how to use variables, procedures (and the components of procedures, such as error handling and flow control), functions, triggers, and temporary tables.