PHP MySQL Order by multiple columns

Question

I am looking to create an order based on multiple columns in my table - all date related. For example: my columns are: fee_due, fee_2_due, fee_3_due - they all contains results of various dates. However, I want to create an order combining all columns, so fee_due might be 2012-11-03, fee_2_due might be 2012-11-01 and fee_3_due might be 2012-11-02.

My query needs to be:

SELECT *
FROM table_name
ORDER BY [date] DESC

... whereby the dates from the 3 columns join to form one order, regardless of what column they are in.

Hope that makes sense and thanks in advance.

Answer 1

Additionally you can:

SELECT *
FROM table_name
ORDER BY fee_due ASC,fee_2_due DESC,fee_3_due DESC

You can sort each column independently according to your need.

Answer 2

I used the following to make it work:

SELECT * FROM table ORDER BY camp1 ASC, camp2 ASC, camp3 DESC