Get the number of digits after the decimal point of a float (with or without decimal part)

Question

I have following list of Amount (float) in my table.

Amount
123
123.1
123.0123
123.789456

How can i get the number of digits a

Answer 1

And one more way:

SELECT  Amount,
        CASE WHEN deci = 0 THEN 0 ELSE LEN(deci) END AS Result
FROM (
    SELECT  Amount,
            TRY_CAST(REVERSE(REPLACE(Amount - TRY_CAST(Amount as int),'0.','')) as int) as deci
    FROM (VALUES
    (123),
    (123.1),
    (123.0123),
    (123.789456)
    ) as t (Amount)
) as t

Output:

Amount      Result
123.000000  0
123.100000  1
123.012300  4
123.789456  6