CREATE TABLE test1 ( a text COLLATE "de_DE", b text COLLATE "es_ES", ...
);
My thought was to add the following example:
SELECT a < (select 'foo' COLLATE "fr_FR") FROM test1;
I thought this would error out because the subquery's result is considered implicit and, in this case, it seems you now have conflicting implicit collations. However, this does not produce an error. What am I missing?
Data, apparently...I got the same non-error result before inserting a record into test1 then I got the expected error.
Its the function/operator the fails when faced with invalid input, not the planner, so the error requires data to provoke.
