Detect overlapping date ranges from the same table

Question

I have a table with the following data

PKey  Start       End         Type
====  =====       ===         ====
01    01/01/2010  14/01/2010  S
02    15/01/2010         


        

Answer 1

I had to do a very similar thing for to stop duplicate holiday being entered into a table. it was in access and written to a temptable on input so had to query it in VBA SQL:

 stCommandText = "SELECT " _
                    & "* " _
                    & "FROM " _
                    & "TableName a, " _
                    & "TableName b " _
                    & "WHERE " _
                    & "a.ID = b.ID " _
                    & "AND a.Startdate >= b.Startdate AND a.StartDate <= b.EndDate " _
                    & "AND a.AutoNo <> b.AutoNo "