v0.5.2

Fixed

• Oracle views: an empty string literal is NULL, as it is in Oracle, wherever it is a value (CASE ... THEN '',
  NVL(x, ''), DECODE, a select item), compared with (x <> '' is never true) or passed to a function
  (LENGTH('') is NULL). It stayed an empty string, so e.g. a CASE returning '' gave non-NULL values
  where Oracle has NULLs. REPLACE, REGEXP_REPLACE and ||, which read NULL as '', behave as before.

• Views: a column reference that matches a column of a table in its own FROM only when case is ignored
  is refused (the view is listed as failed, with the reason). Oracle and Snowflake fold an unquoted
  partno to PARTNO, which doesn't match a quoted "PartNo" column, so they resolve it in an outer
  query; DuckDB names ignore case, so the copied view would bind it to that table and filter differently
  without any error. Add a view override that says which column is meant.