Common Table Expressions (CTE)

Technical Article

Function and Queries to Convert Hierarchical Adjacency to Nested Json Arrays

  • Script

This script converts hierarchical adjacency into nested json rows which contain the recursive "downlines" of each node.  The table-valued function treats each row in the original adjacency as the root node in a recursive common table expression. 

★ ★ ★ ★ ★ ★ ★ ★ ★ ★

You rated this post out of 5. Change rating

2019-11-12 (first published: )

2,171 reads

Stairway to Advanced T-SQL

Stairway to Advanced T-SQL Level 3: Understanding Common Table Expressions (CTEs)

  • Stairway Step

A CTE is a temporary result set defined by a simple query, and is used within the execution scope of a single INSERT, UPDATE, DELETE, or SELECT statement. In this article we will explore how to define and use CTE's.

★ ★ ★ ★ ★ ★ ★ ★ ★ ★

You rated this post out of 5. Change rating

2024-04-03 (first published: )

6,585 reads

Blogs

Goodbye, Microsoft

By

A few years ago I took a new job at Microsoft, working as a...

The SUM of Nothing: #SQLNewBlogger

By

I caught this interesting item over on Pinal Dave’s blog: Eleven Interview Questions that...

How to Move the SSMS Status Bar to the Top and Color-Code SQL Server Connections

By

I use color-coded connections in SSMS to distinguish Production, Pre-Production, UAT, and Development. But...

Read the latest Blogs

Forums

Building a SQL Server Fleet Audit That Leadership Actually Reads

By Mayank Sethi

Comments posted to this topic are about the item Building a SQL Server Fleet...

Smart AI Agents and Data Security

By Steve Jones - SSC Editor

Comments posted to this topic are about the item Smart AI Agents and Data...

RegEx Functions IV

By Steve Jones - SSC Editor

Comments posted to this topic are about the item RegEx Functions IV

Visit the forum

Question of the Day

RegEx Functions IV

I have this data in a table in a SQL Server 2025 database:

EmailAddressID EmailAddress
7              dylan0@ADVENTURE-WORKS.COM
8              Diane1@ADVENTURE-WORKS.COM
If I run this query, which row(s) are returned?
SELECT top 10
 *
 FROM person.EmailAddress
 WHERE REGEXP_LIKE(EmailAddress, '^D', 'i')
 AND BusinessEntityID IN (7,8)

See possible answers