support extract

[alrocar]

See comment

Extract support never worked, and since pg14 it just send the extract to ClickHouse. There's an extract function in ClickHouse but it has nothing to do with Dates.

d_c7d55a=# select floor(extract('epoch' from timestamp) / 60), count(user_id) u from events group by extract('epoch' from timestamp);
d_c7d55a=# select extract('day' from timestamp), count(user_id) u from events group by extract('day' from timestamp);
 extract |   u
---------+-------
      18 | 30600
(1 row)

d_c7d55a=# explain (verbose, costs off) select extract('day' from timestamp), count(user_id) u from events group by extract('day' from timestamp);

Foreign Scan
   Output: (EXTRACT(day FROM t_3849d138311d4f7b98f3fdbb365df222."timestamp")), (count(t_3849d138311d4f7b98f3fdbb365df222.user_id))
   Relations: Aggregate on (t_3849d138311d4f7b98f3fdbb365df222)
   Remote SQL: SELECT toDayOfMonth("timestamp"), count(user_id) FROM d_c7d55a.t_3849d138311d4f7b98f3fdbb365df222 GROUP BY (toDayOfMonth("timestamp"))
(4 rows)

[jesusbotella]

Approving this. Couldn't reproduce tests in my local env. We'll take a look but let's fix the issue.

[alrocar]

I've left only pg14 in ci.yaml, since other versions where failing due to different output and it was being a hell.

I've added a DEVELOPMENT.md with some instructions to debug locally, run tests locally and override the expected files.