[jira] [Commented] (CALCITE-1911) Support within clause in MATCH_RECOGNIZE

["Julian Hyde (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/CALCITE-1911?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16107993#comment-16107993 ] 

Julian Hyde commented on CALCITE-1911:
--------------------------------------

To be clear, this is not in Oracle 12, and it is not in the SQL standard. This is in Oracle fusion middleware's CQL. So, I am not yet convinced we should add this in the current form.

A couple of immediate problems:
* It assumes that there is a system column that defines the timestamp. Only possible in streaming queries, and even then, probably not well defined.
* We should use the SQL standard notation for intervals: {{WITHIN INTERVAL '3' SECONDS}} rather than {{within 3000 milliseconds}}

Cc [~zhiqiang,he]



> Support within clause in MATCH_RECOGNIZE
> ----------------------------------------
>
>                 Key: CALCITE-1911
>                 URL: https://issues.apache.org/jira/browse/CALCITE-1911
>             Project: Calcite
>          Issue Type: Bug
>            Reporter: Dian Fu
>            Assignee: Julian Hyde
>              Labels: match
>
> Window is an important feature for pattern detection, it defines the time duration for the events to match a pattern. Here is an example from [doc|https://docs.oracle.com/middleware/1213/eventprocessing/cql-reference/GUID-34D4968E-C55A-4BC7-B1CE-C84B202217BD.htm#CQLLR2119]:
> {code}
> SELECT T.Ac2, T.Bc2, T.Cc2 
>     FROM S
>     MATCH_RECOGNIZE(
>         MEASURES A.c2 as Ac2, B.c2 as Bc2, C.c2 as Cc2
>         PATTERN (A (B+ | C)) within 3000 milliseconds 
>         DEFINE 
>             A as A.c1=10 or A.c1=25, 
>             B as B.c1=20 or B.c1=15 or B.c1=25, 
>             C as C.c1=15
>     ) as T
> {code}



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