BEx designer- Or condition on dates

Hi All,

I need to extract data using bex query with a condition on start date and end date as .

Start date  From 1/1/2000 to 1/31/2000

OR

End date from 1/1/2000 to 1/31/2000

Which is , all the records that has either startdate or end date as above . If  a record has startdate as 1/21/2000and end date as 2/27/2000  or Null I want it to be captured .can youhelp with suggestions.

Thank you!