Derby
  1. Derby
  2. DERBY-4079

Add support for SQL:2008 <result offset clause> and <fetch first clause> to limit result set cardinality

    Details

    • Type: Improvement Improvement
    • Status: Closed
    • Priority: Major Major
    • Resolution: Fixed
    • Affects Version/s: None
    • Fix Version/s: 10.5.1.1
    • Component/s: SQL
    • Labels:
      None

      Description

      SQL 2008 has added new syntax to support a direct way to limit the
      returned set of rows in a result set. This allows an application to
      retrieve only some rows of an otherwise larger result set, similar to
      the popular LIMIT clauses use in some databases.

      Up till now, in Derby (and SQL) we have had to use the ROW_NUMBER()
      function in a nested subquery to achieve the effect of the <fetch
      first clause>, cf. DERBY-2998, a method which is rather more indirect
      and still not efficient (DERBY-3505), and primarily intended for OLAP
      functionality, perhaps.

      There has been no direct way to achieve the effect of the <result
      offset clause> via SQL.

      Syntax (cf. SQL 2008, section 7.13):
      <result offset clause> ::= OFFSET <n>

      {ROW | ROWS}
      <fetch first clause> ::= FETCH {FIRST | NEXT} [<n>] {ROW | ROWS}

      ONLY

      where <n> is an integer. The two clauses syntactically follow the ORDER BY
      clause in the grammar.

      Note that both ORDER BY and the new clauses above are allowed also in
      subqueries in the new version of the SQL standard (section 7.13). I
      only propose to include this at the top level in DERBY for now. (ORDER
      BY is presently also not allowed in subqueries in Derby since SQL
      didn't allow for this until SQL 2008 either).

      1. derby-4079-1.diff
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        Dag H. Wanvik
      2. derby-4079-1.stat
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        Dag H. Wanvik
      3. derby-4079-2.diff
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        Dag H. Wanvik
      4. derby-4079-2.stat
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      5. derby-4079-3.diff
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      6. derby-4079-3.stat
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      7. derby-4079-docs-1.diff
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      8. derby-4079-docs-1.stat
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      9. derby-4079-docs-1.zip
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      10. derby-4079-docs-2.diff
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        Dag H. Wanvik
      11. DERBY-4079-docs-2.diff
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        Kim Haase
      12. derby-4079-docs-2.stat
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        Dag H. Wanvik
      13. derby-4079-docs-2.zip
        6 kB
        Dag H. Wanvik
      14. derby-4079-fixRtStatsTest.diff
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        Dag H. Wanvik
      15. derby-4079-fixRtStatsTest.stat
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        Dag H. Wanvik
      16. ref.zip
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        Dag H. Wanvik
      17. rrefsqljoffsetfetch.html
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        Kim Haase

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            • Assignee:
              Dag H. Wanvik
              Reporter:
              Dag H. Wanvik
            • Votes:
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              Dates

              • Created:
                Updated:
                Resolved:

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