Templates are rendered improperly when aggregations are used

[gorbak25]

On corrosion commit 85a0aed with the following sql schema

CREATE TABLE foo (
    id INTEGER NOT NULL PRIMARY KEY
);

Templates using aggregation functions like sum or json_group_array render improperly
For ex. with the following rhai template

<%= sql("SELECT sum(foo.id) FROM foo").to_json(#{pretty: true}) %>

The result in an empty database looks like this

[
  {
    "sum(foo.id)": null
  }
]

Then after inserting some values INSERT INTO foo(id) VALUES (1),(2),(3),(4);
the result is

[
  {
    "sum(foo.id)": null
  },
  {
    "sum(foo.id)": 10
  }
]

Then after INSERT INTO foo(id) VALUES (5);
the result is

[
  {
    "sum(foo.id)": null
  },
  {
    "sum(foo.id)": 10
  },
  {
    "sum(foo.id)": 5
  }
]

While I would expect the template to render as

[
  {
    "sum(foo.id)": 15
  }
]

The same issue is present when using json_group_array with the following template <%= sql("SELECT json_group_array(json_object('id', foo.id)) FROM foo").to_json(#{pretty: true}) %>

I would suggest to either disallow aggregations in the query parser or rerun the entire query when new data arrives.

[somtochiama]

@gorbak25 Yes, due to the way subscriptions is currently implemented it isn't suitable for aggregate functions because we run the query for particular primary keys instead of the whole table.

We can temporarily disable aggregate functions while we re-do how subscriptions work to accomodate them.