DF078: Non-ISO standard comparison operator found.

Last modified: June 12, 2025

The topic describes the DF078 T-SQL code analysis rule.

Category

BEST PRACTICE

Message

Non-ISO standard comparison operator found.

Description

To ensure cross-platform and future version compatibility, it is recommended to use ISO standard comparison operators.

Additional information

Using ISO standard comparison operators is recommended over non-ISO standard operators to ensure optimal cross-platform and future version compatibility. While currently acceptable, keep in mind that statements using non-ISO operators might not be supported on other ISO-compliant database management systems. Additionally, non-ISO standard comparison operators may not be supported in future SQL Server versions.

Replace the Non-ISO comparison operators with ISO standard operators:

• Not equal to: Use <> instead of !=
• Greater than or equal to: Use >= instead of !<
• Less than or equal to: Use <= instead of !>

Noncompliant code example

SELECT c.FirstName, c.LastName
FROM dbo.Customer c
WHERE c.Id != 10;
GO
 
SELECT c.FirstName, c.LastName
FROM dbo.Customer c
WHERE c.Id !> 10;
GO
 
SELECT c.FirstName, c.LastName
FROM dbo.Customer c
WHERE c.Id !< 10;
GO

Compliant solution

SELECT c.FirstName, c.LastName
FROM dbo.Customer c
WHERE c.Id <> 10;
GO
 
SELECT c.FirstName, c.LastName
FROM dbo.Customer c
WHERE c.Id <= 10;
GO
 
SELECT c.FirstName, c.LastName
FROM dbo.Customer c
WHERE c.Id >= 10;
GO