How to add a calculated column based on unique values in other row in Power query

[prear]

I have a Table. I have three columns, ID, Date 1 and Date 2. Based on a unique ID, I want to create a New Column (Days) which gives the difference between Date 2 and Date 1 in days. Please can anyone help with this. Thank you.

ID	Date 1	Date 2	New Column (Days)
1	10/10/2022	null
1	null	null
1	null	13/10/2022	3
3	11/10/2022	null
3	null	12/10/2022	1

[prear]

Thank you for your help. It worked!

[olgad · Accepted solution]

Hi, 
Group by min Date 1 and max Date 2