What does "WHERE id <> 0" clause mean in SQL?

Query: SELECT id, name, FROM users u WHERE **id <> 0** LIMIT 50 OFFSET 0

What does开发者_如何学运维 the clause id <> 0 mean here? Does it mean:

id is less than zero or id is greater than zero

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<> means "not equal" (it can also be written as != with some DBMS)

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It means not equal and apparently I have to submit at least 30 characters for my answer.

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It means, "where ID is different from 0".

So, both greater than or less than 0.

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it means that you are fetching all records with an id different than 0 (zero), I've sometimes used this just to check if some record is already saved (if the record has an ID it means is saved).

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It means only include results who's field id has a value of greater or smaller than 0, basically records that have non-zero id's - but really this should not be possible, if it is then I'd recommend reconsidering your table designs.