What Is the WITH Clause in SQL?

by Zahin Rahman In this article, you will learn about the SQL WITH clause, also known as common table expression (CTE). We will go over some examples to demonstrate some of their use cases in light of their benefits. Introduction to the SQL WITH Clause The WITH clause in SQL was introduced in standard SQL to simplify complex long queries, especially those with JOINs and subqueries. Often interchangeably called CTE or subquery refactoring, a WITH clause defines a temporary data set whose output is available to be referenced in subsequent queries.

How to Draw a Christmas Tree in SQL

by Aldo Zelen You can use SQL to manipulate all kinds of data, from huge analytical queries to brief single-purpose statements. But you can also use SQL just for fun, without any business requirements stifling your creativity. So, get out your jolly hat and prepare to sing O Christmas Tree as we create some quirky art with plain old SQL. Today, we’re going to generate some holiday-themed ASCII art, just for fun. That’s right.

Simplify SQL Code: Recursive Queries in DBMS

by Aldo Zelen Hey SQL users! Are you repeating the same query in every report? Are your queries getting too complicated? Use recursive queries to simplify SQL code! Too many SQL reports can lead to clutter on your desktop and in your head. And is it really necessary to code each of them separately? Ad-hoc queries can share much of the same SQL code with managerial reports and even regulatory reports. Suppose you’ve been writing basic SQL code for a while.

How to Organize SQL Queries with CTEs

by Aldo Zelen Common table expressions (CTEs) allow you to structure and organize SQL queries. Knowing how to organize SQL queries is a necessity when you begin to move deeper into SQL, so if you want to become an SQL master, you need to know CTEs. The SQL CTE has been part of standard SQL for some time now. CTEs – which are also called WITH statements – are available in all major RDBMS.

How Recursive Common Table Expressions Work

by Marek Pankowski Recursive Common Table Expressions are immensely useful when you're querying hierarchical data. Let's explore what makes them work. Common Table Expressions (CTEs) are some of the most useful constructions in SQL. Their main purpose is improving query design, which makes queries easier to read. One of the reasons CTEs are so popular is that they let you divide longer queries into shorter subqueries. These are easier to read and edit.