Presenting Data with SELECT

In previous chapters, you learned about the basic lifecycle of data operations. You are now able to create and drop tables and insert data into tables. You also learned how to import data into a relational database as well as export it. All these operations complete the starting and ending operations of the following CRUD lifecycle:

Figure 5.1: CRUD operations

The ultimate goal of data management is to utilize the data to generate analytical information. Reading the stored data is the fundamental step in this process. In this chapter, you will start to learn how to read data from existing tables. In the next chapter, you will learn further operations for data transformation and about the update stage of the lifecycle.

The following topics are covered in this chapter:

• Using SELECT expressions:
  • Expression alias
  • The LIMIT clause
  • The ORDER BY clause
  • The DISTINCT and DISTINCT ON functions
  ...