The hidden cost of a NULL in your exclusion list

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NOT IN expands to `id != 1 AND id != 2 AND id != NULL`. The last condition evaluates to UNKNOWN for any id value, because no value can be proven unequal to an unknown. UNKNOWN ANDed with anything stays UNKNOWN, which the WHERE clause rejects. So even 5 and 10 are excluded - neither passes the filter. Always strip NULLs from a NOT IN list, or rewrite as NOT EXISTS.