Paste this into a new question or an answer at dba.stackexchange.com:
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> select 'x' NOT IN ('a', 'b', NULL)
>
> <pre>
> | 'x' NOT IN ('a', 'b', NULL) |
> | --------------------------: |
> | <em>null</em> |
> </pre>
*db<>fiddle [here](https://dbfiddle.uk/?rdbms=mysql_8.0&rdbms2=mysql_8.0&fiddle=111f1189011651c61f603fc7f69567a9)*
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