sql

As a data engineer, a typical working day for me, apart from meetings, is full of SELECT, FROM and WHERE. But these basic statements are not enough, especially for the complex ad hoc analysis that is increasingly common nowadays. SQL is a powerful language. It is a declarative language where we define what we want and the engine finds a way to achieve it. The language is evolving to adapt to the increasing variety of analysis needs....

In database design, the idea of hierarchical data represents relationships between entities as a tree-like structure. This type of data model is widely used in many domains, such as file systems, organizational structure, etc. When dealing with hierarchical data, it is crucial to efficiently query and extract information about the relationships between entities. In this post, we will explore two powerful SQL tools for querying hierarchical data: recursive Common Table Expressions (CTEs) and the CONNECT BY clause....