Would you argue that automatic scalar-ism is also flawed, and the query

    SELECT a FROM aa;

should have an explicit grouping, like

    SELECT a FROM aa GROUP BY id;

?

After all, when you think about it, it's really not the aggregate functions that break expectations, it's the scalars. Of the four combinations of having or not having an explicit `GROUP BY` and having or not having an aggregate function, three of them have the unsurprising behavior of returning exactly one row per grouping.

    -- aggregate function and group by - one single result per grouping
    SELECT sum(a) FROM aa GROUP BY a; --or
    SELECT sum(a) FROM aa GROUP BY ();


    -- no aggregate function, but a group by - one single result per grouping
    SELECT a FROM aa GROUP BY a;

    -- just aggregate function, but no group by - one single result per (single, implicit) grouping
    SELECT sum(a) FROM aa;

But then, when you have neither an aggregate function nor an explicit `GROUP BY`, it breaks expectations:

    -- no aggregate function, no group by - one result row per row 
    -- in the source set, even though there should be only one big implicit group
    SELECT a FROM aa;

Therefore, I propose that the next SQL standard should introduce a new `GROUP BY INDIVIDUAL ROW` keyword, that henceforth all "scalar" queries MUST use in order to have consistent behaviour with the rest of the language.