Re: BUG #13506: jsonb || operator does not work

gregoire.hubert@pragmafabrik.com writes:
> select val->'a'||val->'c' from (values ($j${"a": {"b": 2}, "c": {"d":
> 3}}$j$::jsonb)) a (val);

You're making unwarranted assumptions about the precedence of those
operators.

(val->'a')||(val->'c') does what you expect.  Working out what the
expression does as-written is left as an exercise for the reader.

            regards, tom lane