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Posted to notifications@asterixdb.apache.org by "ASF subversion and git services (JIRA)" <ji...@apache.org> on 2019/01/17 17:50:00 UTC
[jira] [Commented] (ASTERIXDB-2511) Refactor LET and WHERE clauses
into a single clause list
[ https://issues.apache.org/jira/browse/ASTERIXDB-2511?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16745330#comment-16745330 ]
ASF subversion and git services commented on ASTERIXDB-2511:
------------------------------------------------------------
Commit 276adf98b72b8ad58920067e43eec315d6242353 in asterixdb's branch refs/heads/master from Dmitry Lychagin
[ https://gitbox.apache.org/repos/asf?p=asterixdb.git;h=276adf9 ]
[ASTERIXDB-2511][COMP] Refactor LET/WHERE clauses into a single list
- user model changes: no
- storage format changes: no
- interface changes: no
Details:
- Consolidate LET and WHERE clauses into a single list in the SelectBlock
Change-Id: I9265dfc3adb9ef4d5eb963b0aa4d39c2ad0cc068
Reviewed-on: https://asterix-gerrit.ics.uci.edu/3118
Tested-by: Jenkins <je...@fulliautomatix.ics.uci.edu>
Contrib: Jenkins <je...@fulliautomatix.ics.uci.edu>
Integration-Tests: Jenkins <je...@fulliautomatix.ics.uci.edu>
Reviewed-by: Ali Alsuliman <al...@gmail.com>
> Refactor LET and WHERE clauses into a single clause list
> ---------------------------------------------------------
>
> Key: ASTERIXDB-2511
> URL: https://issues.apache.org/jira/browse/ASTERIXDB-2511
> Project: Apache AsterixDB
> Issue Type: Improvement
> Components: COMP - Compiler
> Reporter: Dmitry Lychagin
> Assignee: Dmitry Lychagin
> Priority: Minor
>
> Currently SelectBlock has a list of LET clauses followed by a single WHERE clause. Some expression tree rewriting rules (e.g. InlineColumnAliasVisitor) ** introduce LET clauses which can only be placed before the WHERE clause because of this design. This approach creates a problem when rewriting window expressions because they might need to be placed after the WHERE clause to maintain the correct semantics.
> The proposal is to consolidate LET/WHERE clauses into a single list in the SelectBlock, so LET clauses can be placed either before or after the WHERE clause. The SELECT statement syntax won't be changed at this point, so it'll continue to support only multiple LET clauses followed by a single WHERE clause.
> LET/HAVING clauses after GROUP BY clause will also be consolidated into a single list.
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