What is the difference between != and <> operators?

postgresql

Solution

From the manual:

Note: The != operator is converted to <> in the parser stage. It is not possible to implement != and <> operators that do different things.

So no, there is no difference between the two.

Problem

I don't like not knowing this as there may be situations when I need to use one instead of the other. It seems in most cases they produce the same results but I am taking a guess they have subtle difference, maybe to do with NULL values or one does strict comparisons like the extra = in PHP does. Thanks

Original source

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