UNION ALL

External Article

UNION vs. UNION ALL in SQL Server

  • Article

Sometimes there is a need to combine data from multiple tables or views into one comprehensive dataset. This may be for like tables within the same database or maybe there is a need to combine like data across databases or even across servers. I have read about the UNION and UNION ALL commands, but how do these work and how do they differ?

2019-12-05

Blogs

Logging in Azure Data Factory data flows

By

(2025-June-15) Long gone are the days when a data engineer could simply focus on building...

ADF: Publish suddenly includes everything where it used to be incremental changes since the last publish

By

I recently encountered an interesting issue with ADF where the publish feature suddenly attempted...

Beginner’s Guide: Create a File Organizer CLI Tool in Rust

By

Image from Afdhaluddin on ShutterstockCLI which is generally referred to as Command Line Interface...

Read the latest Blogs

Forums

How Many Can Be the Greatest

By Steve Jones - SSC Editor

Comments posted to this topic are about the item How Many Can Be the...

How to process images and analyze charts with AI

By Daniel Calbimonte

Comments posted to this topic are about the item How to process images and...

Patching the Patch

By Steve Jones - SSC Editor

Comments posted to this topic are about the item Patching the Patch

Visit the forum

Question of the Day

How Many Can Be the Greatest

I am trying to analyze a number of columns in a large table to determine the highest value for each row. In SQL Server 2022, we have the GREATEST function, which will return the greatest value from those columns passed in. How many columns can I include in an expression like this:

select GREATEST( col1, col2, col3, ...)

See possible answers