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Posted to issues@calcite.apache.org by "duan xiong (Jira)" <ji...@apache.org> on 2021/06/30 01:21:00 UTC
[jira] [Assigned] (CALCITE-4486) UNIQUE predicate
[ https://issues.apache.org/jira/browse/CALCITE-4486?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
duan xiong reassigned CALCITE-4486:
-----------------------------------
Assignee: duan xiong
> UNIQUE predicate
> ----------------
>
> Key: CALCITE-4486
> URL: https://issues.apache.org/jira/browse/CALCITE-4486
> Project: Calcite
> Issue Type: Bug
> Reporter: Julian Hyde
> Assignee: duan xiong
> Priority: Major
>
> Implement the UNIQUE predicate, as specified by the SQL standard.
> Example:
> {code:java}
> UNIQUE (SELECT publishedIn FROM Book
> WHERE authorId = 3)
> NOT UNIQUE (SELECT publishedIn FROM BOOK
> WHERE authorId = 3)
> {code}
> {{UNIQUE}} returns {{FALSE}} if the query returns two or more rows that do not include NULL values and are equal. Like {{EXISTS}}, it never returns {{UNKNOWN}}.
> More details at [JOOQ|https://www.jooq.org/doc/3.0/manual/sql-building/conditional-expressions/unique-predicate/].
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