Understanding the Difference Between <> and != in PostgreSQL

If you work with PostgreSQL, you've likely come across both <> and != operators to compare values. While both are valid, many developers wonder: what's the difference between these two?

Here’s the short answer: there is no functional difference between <> and != in PostgreSQL.

What Do They Do?

Both <> and != are inequality operators. They check if two values are not equal and return:

• TRUE if the values are different
• FALSE if the values are the same

SELECT 1 <> 2; -- Returns TRUE
SELECT 1 != 2; -- Returns TRUE

SELECT 'PostgreSQL' <> 'SQL'; -- Returns TRUE
SELECT 'PostgreSQL' != 'SQL'; -- Returns TRUE

SELECT 1 <> 1; -- Returns FALSE
SELECT 1 != 1; -- Returns FALSE        

Why Do We Have Two Operators?

1. <> is the SQL Standard:
2. != is a Convenience Feature:

Which One Should You Use?

While you can use either, here’s a recommendation:

• If you aim for SQL standard compliance or write queries that might need to work across different database systems, use <>.
• If you’re working in a PostgreSQL-only environment, feel free to use != if it feels more intuitive to you.

Conclusion

In PostgreSQL, <> and != are two sides of the same coin. While their usage boils down to personal or team preference, sticking to the SQL standard (<>) can make your code more portable and consistent.

What about you? Which operator do you prefer to use and why? Let’s discuss in the comments!