[
https://issues.apache.org/jira/browse/CALCITE-3402?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16956606#comment-16956606
]
Julian Hyde commented on CALCITE-3402:
--------------------------------------
Only allowing a single key makes a lot of sense.
If {{i}} is an INTEGER column, you can have {{ORDER BY i RANGE BETWEEN 3
PRECEDING and 5 FOLLOWING}}. The range is an INTEGER expression. Why? Because
when you subtract an INTEGER from an INTEGER, the result is an INTEGER.
If {{t}} is a TIMESTAMP column, you can have {{ORDER BY t RANGE BETWEEN
INTERVAL '3' DAY PRECEDING and INTERVAL '5' DAY FOLLOWING}}. Why? Because when
you subtract a TIMESTAMP from a TIMESTAMP, the result is an INTERVAL.
If you have {{x}} and {{y}} are columns of any type, you can't have {{ORDER BY
x, y RANGE BETWEEN anything AND anything}}, because you can't subtract (x1, y1)
from (x2, y2).
(By the way, I'm pretty sure that PostgreSQL does allow {{ORDER BY t RANGE
BETWEEN INTERVAL '3' DAY PRECEDING and INTERVAL '5' DAY FOLLOWING}}, despite
your assertion that it does not.)
> Allow RANGE with compoud ORDER BY clause
> ----------------------------------------
>
> Key: CALCITE-3402
> URL: https://issues.apache.org/jira/browse/CALCITE-3402
> Project: Calcite
> Issue Type: Improvement
> Components: core
> Affects Versions: 1.18.0, 1.19.0
> Reporter: benj
> Priority: Major
>
> It will be very useful to have the capacity to use compound ORDER BY clause
> with RANGE
> {code:sql}
> apache drill (dfs.tmp)> SELECT a
> , last_value(c) OVER(PARTITION BY a ORDER BY c, b DESC RANGE BETWEEN
> UNBOUNDED PRECEDING AND UNBOUNDED FOLLOWING)
> FROM (SELECT 1 a, 'b' b, 3 c
> UNION SELECT 2, 'c', 4
> UNION SELECT 1, 'c', 4
> /* UNION ... */
> ) x;
> Error: VALIDATION ERROR: From line 2, column 56 to line 2, column 60: RANGE
> clause cannot be used with compound ORDER BY clause
> {code}
> I know it's possible (for last_value) to rewrite with first_value with an
> reverse ORDER BY and without RANGE to obtain correct result.
> But it will become sometimes less readable and request write from other SGBDR
> will not be compatible and should be rewrite, and for some other function
> than last_value, the problem will not be solved like that.
> compound ORDER BY clause with RANGE is possible with some SGBDR like
> Postgres:
> [https://www.postgresql.org/docs/9.3/sql-expressions.html#SYNTAX-WINDOW-FUNCTIONS]
--
This message was sent by Atlassian Jira
(v8.3.4#803005)
