Please don’t top-post. On Tuesday, May 24, 2022, jian he <jian.universal...@gmail.com> wrote:
> > Otherwise, all input expressions must have the same implicit collation >> derivation or the default collation. If any non-default collation is >> present, that is the result of the collation combination. Otherwise, the >> result is the default collation. >> > > I think the above quote part can be used to explain the following > examples. > >> CREATE TABLE test1 ( a text COLLATE "de_DE", b text COLLATE "es_ES", c >> text ); >> SELECT a < 'foo' FROM test1; > > SELECT c < 'foo' FROM test1; > > But the *non-default* seems not that correct for me. Like a column if it does > not mention anything, then the default value is null. So > * create table test111( a tex*t) The default collation for column a is the > same as the output of *show lc_collate*. > > so there is no *non-default? * > > I’m not following the point you are trying to make. table111.a contributes the default collation for any expression needing a collation implicitly resolved. David J.
