Sort by one column and then another?

Hi guys,

I have a list of 'account numbers' with their respective 'next due dates'.
I need to sort this list to be in order of the earliest next due date first. However some account numbers have more than one due date. Ideally I need them in date order but group the account numbers together even if that account number has a due date much further away than the nearest.

Any ideas how to sort an excel file in this way?

If that doesnt make sense ive included below what it would should essentially look like. Sorted by due date but grouped within account number:

Account Number	Next Due Date
1234567	01/12/2020
1234567	04/04/2021
1239898	25/12/2020
1239898	07/07/2021
7245896	03/02/2021
3215648	05/05/2021

I've tried that but its putting the account number in order first regardless of when the next due date is which in a lot of cases is in late 2021 when i have many next due in December 2020.
Switching it the other way (Sort by due date first, then Customer Number) does not work either as it still splits out the customer account numbers.

Originally Posted by Glenn Kennedy

Select both columns. Then use Data/Sort as shown in the image below.

I've tried that but its putting the account number in order first regardless of when the next due date is which in a lot of cases is in late 2021 when i have many next due in December 2020.
Switching it the other way (Sort by due date first, then Customer Number) does not work either as it still splits out the customer account numbers.