Learn PostgreSQL

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 JOIN and common table expressions (CTEs) in depth.

The topics we will talk about will be the following:

• Exploring the SELECT statement
• Using UPSERT
• Exploring CTEs

Exploring the SELECT statement

As we saw in the previous chapter, we can use the SELECT statement to filter our datasets using the equality condition. In the same way, we can filter records using > or < conditions, such as in the following example:

forumdb=# ...