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

RE: primary key based on unique value for two columns

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 12:05 PM To: Brendin Cc: [EMAIL PROTECTED] Subject: Re

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 unique value for two

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

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 many