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mrkeen • yesterday at 9:42 PM • 2 replies • view on HN

Hi apologist. How was the woodwork? Your exact comment was why I wrote mine.

  You could write predicates over non-existent columns:

  root=> SELECT * FROM t
         WHERE definitely_not_a_column = 4;
Cool, definitely_not_a_column doesn't exist, so therefore that whole WHERE clause doesn't exist either, so the real query is SELECT FROM t.

  SELECT * FROM t WHERE 4 = 5;
   a | b
  ---+----
   5 | 6
  (1 row)
We're comparing 4 and 5. Precedent?

  System.out.println(((Integer)4).compareTo((Integer)5));
  > -1
What happens when you treat -1 as a bool? The following languages agree that -1 is true: C, C++, JS, Python, PHP, Ruby, Perl, Lua, R.

So it's SELECT FROM t WHERE true;

Now, let's get busy blaming Jepsen for using the tool wrong.

Replies

debugnik • yesterday at 9:58 PM

> therefore that whole WHERE clause doesn't exist either

No, therefore the condition is unsatisfiable and equivalent to WHERE FALSE. And that's letting you ignore the SQL spec, which says the query is invalid and should return "Column not found" because the column name cannot be resolved.

> We're comparing 4 and 5. Precedent?

I really hope you're trolling, for your own sake.

semiquaver • today at 1:12 AM

Apologist for what?