RE: primary key based on unique value for two columns

This will work thanks... That's what I want a unique key based on two columns. -Original Message- From: Jonathan Hilgeman [mailto:[EMAIL PROTECTED]] Sent: Monday, November 12, 2001 12:09 PM To: 'Brendin'; [EMAIL PROTECTED] Subject: RE: primary key based on uniqu

RE: primary key based on unique value for two columns

lues ("1","3") Note that the combination of the two columns represents a distinct value but column 1 is the same value in both inserts. -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]] On Behalf Of Bill Adams Sent: Monday, November 12, 2001 1

primary key based on unique value for two columns

I would like to have a table that has a primary key defined on a combination of two columns in the table. In other words a unique key based upon the values in two columns. I don't think I am able to do this in mysql. I think you can only have a primary key on one column and not on a combination

RE: Problem with query

Yours is the first and the winner! :) Thanks using is null worked in the query... Do you know why = doesn't work? -Original Message- From: Ravi Raman [mailto:[EMAIL PROTECTED]] Sent: Friday, October 26, 2001 4:00 PM To: Mysql; Brendin Subject: RE: Problem with query hi. first of

Problem with query

I am having a strange problem with a query... I have a table that contains 3 columns and 3,315,599 rows. One of the columns is a date time field. Out of 3,315,599 rows 1,555,157 contain an entry in the date time field and the other 1,760,442 rows contain null in the date time field Here is t

Does repliation impact on performace?

Lets say you have to mysql servers one is going to be a master and one a replication slave. The master is a very fast dual CPU machine with a SCSI raid array. The Slave is a fast single cpu machine with a 7200RPM UDMA 100 hard drive. The slaves purpose is to act as a backup for the master. Wi