ISNULL in SQL Server - Examples & AI Generator

Mastering the ISNULL function in SQL Server can be tricky, especially if you work across different databases where the syntax varies. ISNULL is essential for handling NULL values, but remembering its SQL Server-specific usage takes effort. With AI2sql, you instantly generate production-ready ISNULL queries—no manual coding or memorization required. Join 50,000+ users in 80+ countries streamlining their SQL workflow in under 10 seconds.

ISNULL Syntax in SQL Server

How ISNULL Works

ISNULL replaces NULL values with a specified replacement value in SQL Server.

• Basic Syntax:

ISNULL(expression, replacement_value)

• expression: The value to test for NULL

• replacement_value: Value returned if expression is NULL

ISNULL Examples You Can Generate Instantly

Examples with Business Context

• 1. Fill missing customer emails with a default address:

SELECT CustomerName, ISNULL(Email, 'noemail@company.com') AS ContactEmail
FROM Customers;

• 2. Show order notes or 'No notes provided' if NULL:

SELECT OrderID, ISNULL(OrderNotes, 'No notes provided') AS Notes
FROM Orders;

• 3. Replace NULL product descriptions:

SELECT ProductID, ISNULL(Description, 'Description unavailable') AS ProductDescription
FROM Products;

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Why Use AI2sql Instead of Manual ISNULL Coding

• No need to memorize SQL Server ISNULL syntax

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• Saves time for developers, analysts, and engineers

• Consistent results whether you’re switching databases or learning SQL

For more advanced tools, Try AI2sql Generator or Learn ISNULL in depth.

Frequently Asked Questions

• Q: Does ISNULL exist in databases other than SQL Server?
  A: While ISNULL is specific to SQL Server, other databases use functions like COALESCE or IFNULL. Syntax and results may vary.

• Q: Can ISNULL handle more than two arguments in SQL Server?
  A: No, ISNULL accepts only two arguments. Use COALESCE for multiple fallback values.

• Q: What is the return type of ISNULL?
  A: ISNULL returns the data type of the first argument unless the replacement_value is of a higher precedence type.

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