SQL Interview: 56 String Concatenation Operators

This is a post in the SQL Interview series. These aren’t trick or gotcha questions, they’re just questions designed to scope out a candidate’s knowledge around SQL Server and Azure SQL Database.

Section: Development Level: Intro

Question:

You are writing Azure SQL Database code that needs to concatenate strings.

You have previously used the + operator to do this.

Which other operator can be used for concatenating strings?

Answer:

Azure SQL Database supports the double-pipe || operator for string concatenation.

That is also being added to SQL Server 2005.

2025-06-17