[SQL] Rolling Sum over 90 Calendar date (look back) from given current date in SQL/ Oracle

**Calender_Date** **Customer_ID** **Amount**
01-Jan-21 20211003 59
01-Jan-21 20211005 100
27-Jan-21 20211003 25
25-Feb-21 20211003 188
23-Mar-21 20211005 67
24-Apr-21 20211009 43
25-May-21 20211013 21
26-May-21 20211013 89
11-Jul-21 20211009 65
28-Aug-21 20211003 90


Needed: Considering Customer_ID - Rolling sum over 90 Calendar look back date (from each given current date).

OutPut Required or Desired Result

**Calender_Date** **Customer_ID** **Amount** **SumofLookbackRolling90DayAmount**
1-Jan-21 20211003 59 59
1-Jan-21 20211005 100 100
27-Jan-21 20211003 25 84
25-Feb-21 20211003 188 272
23-Mar-21 20211005 67 167
24-Apr-21 20211009 43 43
25-May-21 20211013 21 21
26-May-21 20211013 89 110
11-Jul-21 20211009 65 108
28-Aug-21 20211003 90 90

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