Count alpha characters in string field in SQL Server

I am using SQL Server Management Studio v17.9.1. I have column in a database table that contains alphanumeric strings. I need to count the letters in the string and produce a table of the aggregate results showing the number of letters by a count of the records which had that number of letters in the column.

I am also trying, if possible, to make the list dynamic so the rows in the aggregated results goes as far as the max number of letters in a string in the table column.

The examples I have found so far look to scan the string character by character which will be very performance intensive and I have also looked at the replace function but it does not look like it works with regex and I would have to replace each letter in the alphabet in turn.

Thanks for any help.

For example: Table1

ID
----------
A00001
AB0001
AC123
CB00AD
1234AD

Aggregated results:

No of letters          Count of records
-----------            -----------        
1                      1
2                      3
3                      0
4                      1

Answer

Just another option using an ad-hoc tally table

Example

Declare @YourTable Table ([ID] varchar(50))
Insert Into @YourTable Values 
 ('A00001')
,('AB0001')
,('AC123')
,('CB00AD')
,('1234AD')

Select Letters
      ,Cnt = count(*)
 From (    
        Select Letters = count(*)
         From  @YourTable A
         Join (
                Select Top (select max(len(ID)) from @YourTable) N=Row_Number() Over (Order By (Select NULL)) From master..spt_values n1
         ) B  on n<=len(ID)
         Where substring(ID,N,1) not like '[0-9]'
         Group By ID
       ) A
 Group By Letters

Returns

Letters Cnt
1       1
2       3
4       1