Finding Duplicate ID's based on an overlapping start and end date

[PowerQueryFTW]

I have a table with a column of IDs with a start and end date for those IDs.  I need a DAX formula that will identify duplicate IDs but only if the start and end dates overlap.  

For example on a 3 column table with the ID, Start Date, End Date.

If the first 3 rows are ID 1.

The first row has a start date of Jan 1 2018 and an end date of jan 31st.  2nd row has start date of Feb 1 and end date of feb 28th.  Thats ok and no duplicate would exist.  However if the 3rd row in this example has a start date of Jan 15 and an end date of Jan 20 then it should flag this ID as a duplicate ID. 

Example File

https://ufile.io/318mh

[Ashish_Mathur · Accepted solution]

Hi,

This is the calculated column formula i wrote

=if(ISNUMBER(CALCULATE(MAX(Data[Start Date]),FILTER(Data,Data[ID]=EARLIER(Data[ID])&&Data[Start Date]<=EARLIER(Data[End Date])&&Data[Start Date]>EARLIER(Data[Start Date])))+CALCULATE(MIN(Data[End Date]),FILTER(Data,Data[ID]=EARLIER(Data[ID])&&Data[End Date]>=EARLIER(Data[Start Date])&&Data[End Date]<>EARLIER(Data[End Date])&&Data[Start Date]<=EARLIER(Data[End Date])))),"Duplicate","OK!")

Hope this helps.

[PowerQueryFTW]

Thank you very much!

[Ashish_Mathur]

You are welcome.