At 15:30 -0400 on 06/23/2004, Michael Stassen wrote about Re: INDEX DESC:
The manual http://dev.mysql.com/doc/mysql/en/CREATE_INDEX.html says An
index_col_name specification can end with ASC or DESC. These keywords are
allowed for future extensions for specifying ascending or descending index
At 16:38 -0400 on 06/23/2004, Michael Stassen wrote about Re: INDEX DESC:
For example, I want to read ranges of values from my db in the opposite
order of how they are currently being indexed without using an extra
ORDER BY in my select. This ORDER BY forces an internal sort to put the
result
Michael Stassen wrote:
SELECT init FROM inits GROUP BY init ORDER BY init;
+--+
| init |
+--+
| A|
| B|
| C|
...
| X|
| Y|
| Z|
+--+
26 rows in set (0.39 sec)
SELECT init FROM inits GROUP BY init ORDER BY init DESC;
+--+
| init |
+--+
| Z|
| Y|
|
Jochem van Dieten wrote:
Michael Stassen wrote:
SELECT init FROM inits GROUP BY init ORDER BY init;
+--+
| init |
+--+
| A|
| B|
| C|
...
| X|
| Y|
| Z|
+--+
26 rows in set (0.39 sec)
SELECT init FROM inits GROUP BY init ORDER BY init DESC;
+--+
| init |
At 11:36 -0400 6/23/04, Alejandro Heyworth wrote:
Does anyone know when INDEX DESC will be implemented?
I'm storing time values and want to access the data from the most
recent time value without sorting the result set.
I don't see any relationship between your two sentences?
--
Paul DuBois,
On Wed, Jun 23, 2004 at 11:36:52AM -0400, Alejandro Heyworth wrote:
Does anyone know when INDEX DESC will be implemented?
I'm storing time values and want to access the data from the most recent
time value without sorting the result set.
Why is sorting required at all? Indexes *are* sorted
I suspect he is refering to 3.23's inability to use an index on a ORDER
BY xxx DESC
Jeremy Zawodny wrote:
On Wed, Jun 23, 2004 at 11:36:52AM -0400, Alejandro Heyworth wrote:
Does anyone know when INDEX DESC will be implemented?
I'm storing time values and want to access the data from the most
Alejandro Heyworth wrote:
Does anyone know when INDEX DESC will be implemented?
I'm storing time values and want to access the data from the most
recent time value without sorting the result set.
Paul DuBois wrote:
I don't see any relationship between your two sentences?
Jeremy Zawodny wrote:
Why
I don't see any relationship between your two sentences?
Thanks for the responses.
I guess I was not clear enough in my last post.
You can define an index to sort values in a particular order... ASC is the
default.
DESC is an option, but it is not implemented yet. I want to know when it
will
On Wed, Jun 23, 2004 at 02:28:15PM -0500, gerald_clark wrote:
I suspect he is refering to 3.23's inability to use an index on a ORDER
BY xxx DESC
In other words ancient history :-)
Jeremy
--
Jeremy D. Zawodny | Perl, Web, MySQL, Linux Magazine, Yahoo!
[EMAIL PROTECTED] |
Alejandro Heyworth wrote:
I don't see any relationship between your two sentences?
Thanks for the responses.
I guess I was not clear enough in my last post.
You can define an index to sort values in a particular order... ASC
is the default.
DESC is an option, but it is not implemented yet. I
Jeremy Zawodny wrote:
On Wed, Jun 23, 2004 at 02:28:15PM -0500, gerald_clark wrote:
I suspect he is refering to 3.23's inability to use an index on a ORDER
BY xxx DESC
In other words ancient history :-)
Not only that, but without ORDER BY, no order is assured.
Jeremy
--
MySQL General
Alejandro Heyworth wrote:
I don't see any relationship between your two sentences?
Thanks for the responses.
I guess I was not clear enough in my last post.
You can define an index to sort values in a particular order... ASC is
the default.
DESC is an option, but it is not implemented yet. I
Subject: Re: INDEX DESC
-Original Message-
From: gerald_clark [mailto:[EMAIL PROTECTED]
Sent: Wednesday, June 23, 2004 1:30 PM
To: Alejandro Heyworth
Cc: [EMAIL PROTECTED]
Subject: Re: INDEX DESC
Alejandro Heyworth wrote:
I don't see any relationship between your two sentences?
Thanks for the responses.
I
Hi Michael,
- Original Message -
From: Michael Stassen
Sent: Wednesday, June 23, 2004 2:30 PM
Subject: Re: INDEX DESC
Jeremy Zawodny wrote:
Why is sorting required at all? Indexes *are* sorted already.
I expect he's referring to mysql's poor performance when doing ORDER
Alejandro Heyworth wrote:
Currently, if I insert integer values into a table with an index ASC
(or DESC) on the INT column , a general SELECT will return the values
in ascending order.
1 2 3 4 5
That may be true, but only because you haven't been adding and deleting
records. It's not something
That could be. If so, it's a MySQL 3.23 limitation that was fixed in
MySQL 4.0.
So, what we are agreeing on is that MySQL 4.x does in fact support both
DESC and ASC indexes?
If this is the case and we're doing something wrong here, cool!
I definitely think the docs should reflect this
At 17:06 -0400 6/23/04, Alejandro Heyworth wrote:
That could be. If so, it's a MySQL 3.23 limitation that was fixed in
MySQL 4.0.
So, what we are agreeing on is that MySQL 4.x does in fact support
both DESC and ASC indexes?
No, what we're saying is that in 3.23, MySQL did not efficiently
Hi Gerald,
- Original Message -
From: gerald_clark
Sent: Wednesday, June 23, 2004 2:28 PM
Subject: Re: INDEX DESC
I suspect he is refering to 3.23's inability to use an index on a ORDER
BY xxx DESC
That's not always true. 3.23 WILL use the index for ORDER BY ... DESC in a
query like
At 16:09 -0400 6/23/04, Alejandro Heyworth wrote:
I don't see any relationship between your two sentences?
Thanks for the responses.
I guess I was not clear enough in my last post.
You can define an index to sort values in a particular order... ASC
is the default.
DESC is an option, but it is
At 15:30 -0400 6/23/04, Michael Stassen wrote:
Alejandro Heyworth wrote:
Does anyone know when INDEX DESC will be implemented?
I'm storing time values and want to access the data from the most
recent time value without sorting the result set.
Paul DuBois wrote:
I don't see any relationship
Matt W wrote:
Hi Michael,
- Original Message -
From: Michael Stassen
I expect he's referring to mysql's poor performance when doing ORDER BY
indexed_column DESC relative to ORDER BY indexed_column ASC.
The performance is only poor when using an index for DESC, *if the index is
PACKED*.
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