View definition falls in rule.sql for specific cases

[shubham-yb]

Boiled down to group by behaviours when dealing with views.

Case 1: All columns specified in the view must be a part of the group by statement. Or the DDL creation will fail.
ex:

create table foo(n1 int, n2 int);
create view v1 as select n1,n2 from foo group by n1;

ERROR:  column "foo.n2" must appear in the GROUP BY clause or be used in an aggregate function
LINE 1: create view v1 as select n1,n2 from foo group by n1;

Case 2: However there’s an exception to this. If all the columns which are a part of the primary key of the tables used for the view are present in the group by clause, DDL creation will go through.
ex:

alter table foo add constraint foo_pk primary key(n1);
create view v1 as select n1,n2 from foo group by n1;
CREATE VIEW

If the view is created using this exception, the correct DDL will fall under rule.sql and the incorrect DDL will fall under view.sql
rule.sql

CREATE OR REPLACE VIEW public.v1 AS
 SELECT foo.n1,
    foo.n2
   FROM public.foo
  GROUP BY foo.n1;

view.sql

CREATE VIEW public.v1 AS
SELECT
    NULL::integer AS n1,
    NULL::integer AS n2;

Case 3: If the group by clause has all the columns mentioned in the view, the DDLs will fall under expected files.

create view v2 as select n1,n2 from foo group by n1,n2;
CREATE VIEW

view.sql

CREATE VIEW public.v2 AS
 SELECT foo.n1,
    foo.n2
   FROM public.foo
  GROUP BY foo.n1, foo.n2;