"Dawid Kuroczko" <qnex42@gmail.com> writes:
> What troubles me here is that surprise factor is unusally high here.
> While I understand mechanics why IN (1) works while IN (1,2) does not,
> I think random developers are going to be confused.
If you're not testing against 8.3 then this argument doesn't carry much
weight. 8.3 will reject *both* cases in the examples you've mentioned.
> PS: I wonder why explicitly using IN (ARRAY[...]) works.
Um, it does not work AFAICS:
regression=# select 'foo'::varchar in (array[1,2,3]);
ERROR: operator does not exist: character varying = integer[]
LINE 1: select 'foo'::varchar in (array[1,2,3]);
^
HINT: No operator matches the given name and argument type(s). You may need to add explicit type casts.
regards, tom lane