Re: UPDATE question
On 5/3/06, Barry [EMAIL PROTECTED] wrote: Cummings, Shawn (GNAPs) schrieb: If I have 4 Fields (FIELD1, FIELD2, FIELD3 FIELD4) I can do this easily; UPDATE TABLE_NAME SET FIELD4 = FIELD1; But -- how do I do it so that FIELD4 = FIELD1 FIELD2 ??? I can't seem to find any examples online. Maybe it's just too early in the morning - I'm drawing a blank! ;) FIELD4 = FIELD1 FIELD 2? Field 4 should be field 1 AND field 2? Can't decide which one field4 should get? :P Well, every child learns that 1 and 1 is 2 ;-P -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe:http://lists.mysql.com/[EMAIL PROTECTED]
Re: How to select the last entry per item
On 4/27/06, Brian J. Matt [EMAIL PROTECTED] wrote: As the items move new time stamped entries are added to the database. How would you query to find the current location of all the items currently in the system. As you might expect we don't want to replace the entry for an item when a location update is made because we need to keep the history. We plan on removing items after a suitable delay when they reach their destination. If you are looking to obtain a result set the represents the current location of all items in the system you can use a sub-select as follows: SELECT item_id AS lid,location,status,timestamp FROM xyz WHERE timestamp=( SELECT MAX(timestamp) FROM xyz WHERE item_id=lid ) For the sake of efficiency make sure you have a key on timestamp. Hope this helps, Tez -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe:http://lists.mysql.com/[EMAIL PROTECTED]
Re: mySQL Backups
On 4/12/06, Tim Lucia [EMAIL PROTECTED] wrote: Would you not lock tables on the slave? The idea of catching it up implies this is way it is done. Catching up means once replication can proceed once the tables are unlocked (on the slave). At least that is the way I read it... On the slave I perform a slave stop, (optional) lock tables, mysqldump, slave start. Since the slave is a dedicated backup instance, and is never connected to directly by applications, the backup is entirely transparent to database users. My suggestion is for the purpose of simplifying such a setup such that it can be performed from a single MySQL instance. Tez -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe:http://lists.mysql.com/[EMAIL PROTECTED]
mySQL Backups
On 4/11/06, Dana Diederich [EMAIL PROTECTED] wrote: We use a dedicated replicated instance for backups. Every night, we lock all of the tables, and dump all of them to compressed files, and unlock them afterwards. It takes a while to catch up, but that doesn't hurt anything. I too use this solution, but it occurs to me that it would be useful if it were possible to replicate one database into another (differently named) database on the same mysql instance for the very purpose of taking snapshots without locking tables in the live system. I realise that it is possible to do this by running two local mysql instances, but a local replicator could be an interesting interim backup solution. Might something like this be on the agenda, or would the planned holistic backup solution eclipse such a feature. Thanks, Tez -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe:http://lists.mysql.com/[EMAIL PROTECTED]
CREATE TABLE x AS with ENGINE = ARCHIVE
Hi, I'm using MySQL 4.11. Is it possible to use the CREATE TABLE x AS syntax alongside the ENGINE = x pragma, since this would make archiving of tables very simple. I require something along the lines of this: CREATE TABLE old AS SELECT * FROM request_log ENGINE=ARCHIVE If this cannot be done then I can always get equivalent functionality by performing CREATE TABLE x (...) ENGINE=x followed by INSERT INTO x SELECT * FROM x, however this is not so neat since it require knowledge of the source table structure which makes it less ideal for automation. Many thanks, Tez -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe:http://lists.mysql.com/[EMAIL PROTECTED]
Re: CREATE TABLE x AS with ENGINE = ARCHIVE
On 3/28/06, Pure Web Solution [EMAIL PROTECTED] wrote: I dont think that it is possible to specify the engine when creating a table this way, you could however create the table using the: CREATE TABLE old AS SELECT * FROM request_log and then issue an alter table command setting the engine to whatever you like. Thanks Paul, That solution seems a little wasteful in terms of resources though. If there is no nice way to achieve this operation then do people think that it would be a good idea to push for the inclusion of this functionality. If more folks than myself can see the benefit in this then please speak up, in which can I'll cross post this to the development list to see what the devs make of it. Warm regards, Tez -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe:http://lists.mysql.com/[EMAIL PROTECTED]
Re: CREATE TABLE x AS with ENGINE = ARCHIVE
On 3/28/06, Peter Brawley [EMAIL PROTECTED] wrote: I require something along the lines of this: CREATE TABLE old AS SELECT * FROM request_log ENGINE=ARCHIVE CREATE TABLE tblname ENGINE=archive SELECT * FROM request_log; PB Excellent. Exactly what I need. Thanks :-) -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe:http://lists.mysql.com/[EMAIL PROTECTED]
