Hi John,
Yes, that looks right to me.
Baron
Kebbel, John wrote:
Same situation, but let's say it's not preceding_quarter and
current_quarter for the table names. To make the flow of records more
clear, let's say the one I was calling preceding_quarter is now called
keepers and the one I called current_quarter is now called
pickThroughThenDelete. I'll delete the pickThroughThenDelete table after
I've found and transferred the new students. Would this syntax work?
insert into keepers select pickThroughThenDelete.* from
pickThroughThenDelete left outer join keepers using(student_id) where
keepers.student_id is null;
drop table pickThroughThenDelete;
-----Original Message-----
From: Baron Schwartz [mailto:[EMAIL PROTECTED]
Sent: Friday, June 01, 2007 10:35 AM
To: Kebbel, John
Cc: mysql@lists.mysql.com
Subject: Re: Find and Add Unmatched Records
Hi John,
Kebbel, John wrote:
I have a table of middle school students I want to update quarterly. I
am only interested in finding and adding new students (not in finding
and deleting students who have been dropped from the school district).
I'm pretty sure I could put together a PHP script that would do this,
but is there a MySQL way for one MySQL table (preceding quarter) to
scan another MySQL table (current quarter) by primary key (student id
number) and absorb the unmatched, new students? I'm thinking that if f
I could bypass PHP, I could use MySQL triggers to automatically add
new records to other, related tables.
It sounds to me like you want an "exclusion join":
insert into new_students(...)
select current_quarter.*
from current_quarter
left outer join preceding_quarter using(student_id) where
preceding_quarter.student_id is null;
Baron
--
Baron Schwartz
http://www.xaprb.com/
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