Leveling Up with SQL: Advanced Techniques for Transforming Data into Insights

© The Author(s), under exclusive license to APress Media, LLC, part of Springer Nature 2023

M. SimonLeveling Up with SQLhttps://doi.org/10.1007/978-1-4842-9685-1_7

7. Working with Subqueries and Common Table Expressions

Mark Simon¹  

(1)

Ivanhoe VIC, VIC, Australia

 

Running a SELECT statement, assuming that there’s no error, gives you a result. That result is a virtual table, and it will have rows and columns.

For our purposes, we are interested in three possible virtual tables:

• One row and one column: You get just one value, though technically it’s still in a table. We’ll call this a single value.

• One column and multiple rows: When the time comes, we’ll call this a list.

• Multiple rows and multiple columns: In this context, a single row with multiple ...