On Wed, 27 Jan 2016 14:38:41 -0500 Richard Hipp <drh at sqlite.org> wrote:
> > See https://www.sqlite.org/nulls.html > The most important part to me, is this one: > The fact that NULLs are distinct for UNIQUE columns but are indistinct for > SELECT DISTINCT and UNION continues to be puzzling. It seems that NULLs > should be either distinct everywhere or nowhere. And the SQL standards > documents suggest that NULLs should be distinct everywhere. Yet as of > this writing, no SQL engine tested treats NULLs as distinct in a SELECT > DISTINCT statement or in a UNION. SQLite is pragmatic, that's fair enough and this paragraph shows this decision was with awareness of the semantic issue. Hard to do better?? Thanks for your insight to both of you. -- Yannick Duch?ne
