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https://issues.apache.org/jira/browse/PHOENIX-1516?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14243230#comment-14243230
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James Taylor commented on PHOENIX-1516:
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Thanks for the patch, [~lhofhansl]. Looks like some RDBMS use RAND as the
function name and allow an optional integer seed argument:
http://msdn.microsoft.com/en-us/library/ms177610.aspx while others like
Postgres use RANDOM and have a separate way to set the seed:
http://www.techonthenet.com/postgresql/functions/random.php while Oracle has a
dbms_random.random that can be used... Sigh... That's not much help. :-(
I do think It's important that we follow the SQL standards as this is what our
users expect, though. If it's not specified, then IMHO we should follow what
other databases do. [~julianhyde] - do you know off the top of your head how
RAND built-in *should* work? In particular, what would this return?
{code}
SELECT RAND() A, RAND() B FROM T LIMIT 2;
{code}
IMO, the same expression should return the same value when used multiple times
in the same statement. Otherwise, we couldn't do any common expression
factoring.
FWIW, I found this interesting blog:
http://blogs.lessthandot.com/index.php/DataMgmt/DataDesign/sql-server-set-based-random-numbers/.
So it looks like SQL Server doesn't even vary the random number for different
rows.
IMO, we should use RAND( [ seed] ) and have it evaluate once per row.
> Add RANDOM built-in function
> ----------------------------
>
> Key: PHOENIX-1516
> URL: https://issues.apache.org/jira/browse/PHOENIX-1516
> Project: Phoenix
> Issue Type: Bug
> Reporter: Lars Hofhansl
> Assignee: Lars Hofhansl
> Attachments: 1516.txt
>
>
> I often find it useful to generate some rows with random data.
> Here's a simple RANDOM() function that we could use for that.
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