> The same applies with two people known to have no middle name—where you store ... | Hacker News

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progval on April 27, 2020 | parent | context | favorite | on: SELECT wat FROM sql

> The same applies with two people known to have no middle name—where you store a zero length string.

I think that's the thing. People use NULL to mean empty value, instead of unknown value.

Not necessarily for strings because there's the empty string, but for numeric fields, including foreign keys

sjwright on April 27, 2020 [–]

Admittedly non-string fields do make me wish for two kinds of NULL so I can differentiate between zero, confirmed-nothing and unknown. But it's never been an issue for me in practice.

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