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Posted to dev@calcite.apache.org by "Julian Hyde (Jira)" <ji...@apache.org> on 2021/02/03 18:36:00 UTC

[jira] [Created] (CALCITE-4486) UNIQUE predicate

Julian Hyde created CALCITE-4486:
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             Summary: UNIQUE predicate
                 Key: CALCITE-4486
                 URL: https://issues.apache.org/jira/browse/CALCITE-4486
             Project: Calcite
          Issue Type: Bug
            Reporter: Julian Hyde


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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