[sqlite] Why is empty string not equal to empty blob?

[Florian Weimer]

* Paul:

> Maybe this question was already asked and explained.
> Or maybe it is documented somewhere (could not fiund it).
> Sorry, if this is the case, but why does
>
> SELECT '' = x'';
>
> yields 0?

In SQLite, string literals have manifest type string.  This is
different from SQL, where string literals have unknown type and are
automatically cast as needed.

sqlite> SELECT '1' = 1;
0

I think SQL92 requires the expression to be true.