Is Not A Valid Identifier. Sql Server

SQL Programming

Hey there! Today, I want to dive into the world of SQL Server and talk about why “is not a valid identifier” is such an important concept to understand. As someone who has worked extensively with SQL Server, I can tell you that encountering this error message can be quite frustrating, but fear not! I’m here to break it down for you and provide some personal insights along the way.

What is an Identifier in SQL Server?

In SQL Server, an identifier is a name that is used to uniquely identify various database objects such as tables, columns, views, stored procedures, and more. These identifiers can be names that we assign, such as table names or column names, or they can be system-generated names like those used for temporary tables or temporary stored procedures.

It’s important to note that SQL Server has certain rules and restrictions when it comes to naming these identifiers. Failure to follow these rules can lead to the dreaded “is not a valid identifier” error message.

Understanding the Error Message

When you encounter the “is not a valid identifier” error message, it means that the name you have provided for an identifier violates one or more of the naming rules imposed by SQL Server. Let’s take a closer look at some common reasons why this error occurs:

  1. Illegal Characters: SQL Server has a specific set of characters that are allowed in identifier names. If you use any characters outside of this set, such as special characters or spaces, you will receive the error message. For example, if you try to create a table with the name “my table”, you will encounter this error.
  2. Reserved Keywords: SQL Server has a list of reserved keywords that have special meanings within the SQL language. If you try to use one of these keywords as an identifier, you will receive the error message. For instance, if you attempt to name a table “select”, you will encounter this error.
  3. Length Limitations: SQL Server imposes length limitations on identifier names. If you exceed these limitations, you will receive the error message. For example, if you try to create a table with a name longer than 128 characters, you will encounter this error.

It’s crucial to pay close attention to these rules and ensure that your identifier names comply with them. Doing so will save you valuable time and frustration in the long run.

Best Practices for Identifier Naming

Now that we understand why the “is not a valid identifier” error occurs, let’s discuss some best practices for naming identifiers in SQL Server:

  • Be Clear and Descriptive: Choose identifier names that accurately describe the object they represent. Avoid using vague or ambiguous names that can lead to confusion.
  • Use Camel Case: For multi-word identifiers, it is common practice to use camel case. This means starting each word with a capital letter (except the first word).
  • Avoid Reserved Keywords: Familiarize yourself with the list of reserved keywords in SQL Server and avoid using them as identifier names.
  • Keep it Concise: Try to keep your identifier names concise and to the point. Long identifier names can be difficult to read and may lead to errors.


In conclusion, understanding why “is not a valid identifier” is such an important concept in SQL Server is crucial for developing efficient and error-free database solutions. By following the naming rules and best practices discussed in this article, you can avoid encountering this error message and ensure smooth operation of your SQL Server databases.

Remember, having a solid grasp of identifier naming conventions will not only make your code more readable but will also save you from countless hours of debugging. So, embrace good naming practices and happy coding!