<html><body><p><br></p><p>><span style="color: rgb(0, 0, 0); font-family: Arial, sans-serif; line-height: 16px; ">I realize RRD is not an ANSI SQL compliant database</span></p><p><font color="#000000" face="Arial, sans-serif"><span style="line-height: 16px;"><br></span></font></p><p><font color="#000000" face="Arial, sans-serif"><span style="line-height: 16px;">Correct. Even the rrd isn't a database at all.</span></font></p><p><font color="#000000" face="Arial, sans-serif"><span style="line-height: 16px;"><br></span></font></p><p><font color="#000000" face="Arial, sans-serif"><span style="line-height: 16px;">jh</span></font></p><p><font color="#000000" face="Arial, sans-serif"><span style="line-height: 16px;"><br></span></font>---------- Původní zpráva ----------<br>Od: Pablo Sanchez <pablo@blueoakdb.com><br>Datum: 30. 10. 2012<br>Předmět: Re: [rrd-users] Newby questions</p><blockquote>[ Comments below, in-line ]<br><br>On 10/29/2012 06:57 PM, Tobias Oetiker wrote:<br>> Today Pablo Chacin wrote:<br>><br>>> For example:<br>>><br>>>> 0:UNKN 300:10 600:10 900:10<br>>>><br>>>> consolidated and then mulitplied by the period will produce the<br>>>> same value as if all entries were 10, and not with one UNKN (given<br>>>> the cf is 0.5). A SUM function would nicely return 30.<br>>>><br>><br>> otoh, why would you want to count UNKNOWN as ZERO ? isn't more<br>> corect to asume that the values during the time where you have no<br>> information were the same as in over the rest of the interval ?<br><br>Hey Tobi,<br><br>I realize RRD is not an ANSI SQL compliant database (*grin*) ... some<br>confusion might arise that in a database, NULL (unknown) is not<br>sum()'d:<br><br>--8-<---8-<---8-<---8-<---8-<---8-<---8-<--<br>19:05:23 plugh > insert into tobi values (1);<br><br>1 row created.<br><br>Elapsed: 00:00:00.00<br>19:05:31 plugh > insert into tobi values (4);<br><br>1 row created.<br><br>Elapsed: 00:00:00.01<br>19:05:36 plugh > insert into tobi values (8);<br><br>1 row created.<br><br>Elapsed: 00:00:00.00<br>19:05:38 plugh > insert into tobi values (null);<br><br>1 row created.<br><br>Elapsed: 00:00:00.00<br>19:05:44 plugh > commit;<br><br>Commit complete.<br><br>Elapsed: 00:00:00.10<br>19:05:46 plugh > select * from tobi;<br><br>SOME_COLUMN<br>-----------<br> 1<br> 4<br> 8<br><br><br>Elapsed: 00:00:00.01<br>19:05:49 plugh > select sum(some_column) from tobi;<br><br>SUM(SOME_COLUMN)<br>----------------<br> 13<br><br>Elapsed: 00:00:00.00<br>19:05:58 plugh ><br>-- <br>Pablo Sanchez - Blueoak Database Engineering, Inc<br>Ph: 819.459.1926 Blog: <a href="http://pablo.blog.blueoakdb.com">http://pablo.blog.blueoakdb.com</a><br>Fax: 760.860.5225 (US)<br><br>_______________________________________________<br>rrd-users mailing list<br>rrd-users@lists.oetiker.ch<br><a href="https://lists.oetiker.ch/cgi-bin/listinfo/rrd-users">https://lists.oetiker.ch/cgi-bin/listinfo/rrd-users</a></blockquote></body></html>