> Surely if it were beneficial you'd see more people doing it, but I have literally never encountered software outside of SQL that does it. Do you see SQL as s

> Surely if it were beneficial you'd see more people doing it, but I have literally never encountered software outside of SQL that does it. Do you see SQL as some weird little edge case of data management? 99.9% of all serious data management happens in a database server with a SQL interface. Maybe other languages don't implement 3-valued logic because they don't need it, because they don't need to do data management, because they'd be bad at data management. It's not even true that languages outside SQL don't have 3-valued logic. They may not have it built into the base language, but analytics packages like Python/pandas and R certainly have some version of a null or NA, and nobody would question the value of it for a second. And databases are typically implemented using C/C++, so there's another example of someone using a general-purpose programming language to implement 3-valued logic (as part of the SQL implementation that is written in C/C++). It's not like SQL is some weird separate language on a different planet as your favorite general purpose programming languages. It's implemented with those languages. So there's your 3-valued implementation right there. When the feature is valuable, it's implemented, and not before.