But then I tried:
+DO $$
+DECLARE
+ a jsonb := '{"": 6, "NU": [{"": [[3]]}, [6], [2], "bCi"], "aaf": [-6, -8]}'::jsonb;
+BEGIN
+ WHILE a IS NOT NULL
+ LOOP
+ RAISE NOTICE '%', a;
+ a := COALESCE(a."NU", a[2]);
+ END LOOP;
+END
+$$ LANGUAGE plpgsql;
+NOTICE: {"": 6, "NU": [{"": [[3]]}, [6], [2], "bCi"], "aaf": [-6, -8]}
+ERROR: missing FROM-clause entry for table "a"
+LINE 1: a := COALESCE(a."NU", a[2])
+ ^
+QUERY: a := COALESCE(a."NU", a[2])
+CONTEXT: PL/pgSQL function inline_code_block line 8 at assignment
which suggests the plpgsql parser does not recognize a."NU" as we'd expect. Any thoughts on this?
I should mention that
+DO $$
+DECLARE
+ a jsonb := '{"": 6, "NU": [{"": [[3]]}, [6], [2], "bCi"], "aaf": [-6, -8]}'::jsonb;
+BEGIN
+ WHILE a IS NOT NULL
+ LOOP
+ RAISE NOTICE '%', a;
+ a := COALESCE((a)."NU", (a)[2]);
+ END LOOP;
+END
+$$ LANGUAGE plpgsql;
+NOTICE: {"": 6, "NU": [{"": [[3]]}, [6], [2], "bCi"], "aaf": [-6, -8]}
+NOTICE: [{"": [[3]]}, [6], [2], "bCi"]
+NOTICE: [2]
works fine. I guess that is good enough. Should we add these to the sql/jsonb.sql to document the expected behavior, both with the error when using plain "a" and with the correct output when using "(a)"? The reason I mention this is that the plpgsql parser might get changed at some point, and without a test case, we might not notice if this breaks.
