Advanced Statements
In the previous chapter, we started taking our first steps with PostgreSQL. In this chapter, we will analyze the SQL language more deeply and write more complex queries. We will talk about SELECT/INSERT/UPDATE again, but this time, we will use the more advanced options surrounding them. We will then cover joins, common table expressions (CTEs), and merge in depth.
The topics we will talk about will be the following:
- Exploring the 
SELECTstatement - Using 
UPSERTandMERGE - Exploring CTEs