phoenix-dev mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "Maryann Xue (JIRA)" <>
Subject [jira] [Updated] (PHOENIX-167) Support semi/anti-joins
Date Thu, 14 Aug 2014 03:06:13 GMT


Maryann Xue updated PHOENIX-167:

    Issue Type: Sub-task  (was: Task)
        Parent: PHOENIX-1167

> Support semi/anti-joins
> -----------------------
>                 Key: PHOENIX-167
>                 URL:
>             Project: Phoenix
>          Issue Type: Sub-task
>            Reporter: James Taylor
>            Assignee: Maryann Xue
>              Labels: enhancement
> A semi-join between two tables returns rows from the first table where one or more matches
are found in the second table. The difference between a semi-join and a conventional join
is that rows in the first table will be returned at most once. Even if the second table contains
two matches for a row in the first table, only one copy of the row will be returned. Semi-joins
are written using the EXISTS or IN constructs.
> An anti-join is the opposite of a semi-join and is written using the NOT EXISTS or NOT
IN constructs.
> There's a pretty good write-up [here] (
on semi/anti joins.

This message was sent by Atlassian JIRA

View raw message