Hi,
You are a bit on the wrong track - a join is a purely temporary thing, and
it would be an error for it to modify the database.
Perhaps what you are thinking of is a 'View', where the results of a select
appear like a table to the user. MySQL doesn't support them (yet).
Your command was trying to churn out 8077 * 8077 = 65,237,929 rows each with
298 columns. No wonder it took a long time.
Regards
Quentin
-----Original Message-----
From: Paul Krohn [mailto:[EMAIL PROTECTED]]
Sent: Thursday, 8 February 2001 14:06
To: [EMAIL PROTECTED]
Subject: JOIN trouble
hi there. i've just joined the list. I took a look through the archives
and I think I've got the whole concept of JOIN wrong, but here goes.
Here's the task: I've got three tables, each with the same number of
records (8077, fwiw). they have 149, 149, and 80 columns.
There are a few columns that appear in all the tables and have identical
content; LOGRECNO is the field that uniquely identifies each record.
What I'd like to do is combine the tables, so that I have 1 table that
is 368 columns wide.
here's what I did, hoping to join the first and second tables:
select * from 2000sampledata1 LEFT JOIN 2000sampledata2 on
2000sampledata1.LOGRECNO = 2000sampledata2.LOGRECNO ;
This causes the database to churn for about 40 minutes (it's a 300 MHz
system with mirrored SCSI disks). In addition, the tables are not, as
far as I can detect, altered in any way. After this command is done, the
database files are the same size in bytes and appear to have not been
modified.
I feel like I'm totally on the wrong track ... any suggestions about how
to accomplish this seemingly simple task would be most appreciated.
--
Paul Krohn - Systems Engineer
San Francisco Chronicle
415-777-7884 - [EMAIL PROTECTED]
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