SQL: retrieve only the records whose value has changed

Question

Sorry for the nondescript title. I\'ll edit as we go along.

I have a table RateTable:

| Code   |  Date     |   Rate  |

  B001     2009-         


        

Answer 1

I would add [ModifiedDate] column to your table and update it's value each time new record is inserted or updated. Then you will be able to get data from the table based on that column:

SELECT * FROM [YourTable] WHERE [ModifiedDate] > '2008-01-20 10:20'