Mark wrote:
-----Original Message-----
From: Chris [mailto:[EMAIL PROTECTED]
Sent: maandag 14 augustus 2006 3:55
To: Mark
Cc: mysql@lists.mysql.com
Subject: Re: Random SELECT on subset
In Perl, I'm trying to get 4 random entries from a subset
"WHERE processed
= '1'" and "columnId" is unique. Like so:
$sth = $dbh->prepare ("SELECT columnId FROM queue WHERE
columnId >= (SELECT FLOOR(MAX(columnId) * RAND()) FROM
queue) IN
(SELECT columnId FROM
queue WHERE processed = '1') ORDER BY columnId LIMIT 4");
I'm not even sure what you're trying to get here!
Could you provide some sample data (5 rows) and what you want
the query to return?
Well, there are a great many colums in the real rows, but say they are like
this:
columnID, picturename, processed, ....
1 name1 1
2 name2 0
3 name3 1
4 name4 1
5 name5 1
6 name6 0
7 name7 1
Then I want to select 4 random columnIDs, but only from the subset
WHERE processed = '1' (so, from the group 1,3,4,5,7).
This query should do what you want:
SELECT columnID from table where process='1' order by rand() limit 4;
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