support noop group by clause

[bluestreak01]

This SQL errors out unnecessarily:

select x, sum(y) from tab group by x

group by x must be consumed and validated to allow friction free user experience

[lbowman]

@bluestreak01 Is this an intentional change from the docs: http://questdb.io/docs/sqlExtensions#important-differences-from-standard-sql

"We do not support explicit GROUP BY clause."

Is the idea then to validate that the provided group by clause matches the implied grouping and then effectively ignore it?

[TheTanc]

Yes this is intentional. We noticed a lot of users were unaware of the implicit grouping. So they tried GROUP BY clauses and got error messages.

As a first step, it could validate the columns and let the implicit group by perform in the background. This would remove 99.99% of the friction and make it easier to migrate existing queries to QuestDB.

[den-crane]

about migration, Mysql does the opposite. It applies any() if a column not mentioned in group by

select a, sum(b) from (select 1 a, 1 b union all select 333, 1) x;
+------+--------+
| a    | sum(b) |
+------+--------+
|    1 |      2 |
+------+--------+

[bluestreak01]

we do the same, that said it looks like SQL in MySQL has mulfunctioned? There should be two keys in the output, as below?

[den-crane]

by default / with disabled strictness

if one execute select a, sum(b) (without group by section) mysql does select any(a), sum(b) group by 1