>>>>You can see my solution in the thread I mentioned to Tore - I also first need to convert to decimal and make a pick on the precision. I chose 11 digits as using higher precision changes the original number (as it was float 0.99 it will become 0.98000089, something like that).
>>>
>>>Find the number of decimal of a float is a waste of time,
>>>because a solution does not exist.
>>>Some floats have an infinite number of decimal places,
>>>so we must first convert them into decimals.
>>>At this point the problem becomes to find the number of decimal places of a decimal ...
>>
>>I agree. So, how do you find a number of decimal places of a decimal?
>
>1. you design the db then you known
>2. COLUMNPROPERTY(..,'SCALE')
>3.
>

>-- this work with 1 or more decimals
>select	CHARINDEX('.',REVERSE(NULLIF(CAST(Value % 1 as varchar(40)))))-1
>-- with 0 decimals, CASE WHEN Value % 1=0 THEN 0 ...
>

Something is wrong at the last step - can you clarify?

declare @t table (Value float null)
insert into @t
select
-41139.99
union all select
10062.99
union all select
1600000
union all select
134979.87
union all select
-154062.04
union all select
-153832.17
union all select
-1235677.922308
union all select
null

select	T.value, F.*, F1.*, F2.* from @t T
cross apply (select CAST(Value as decimal(38,11)) as nValue) F
cross apply (select	CAST(nValue % 1 as varchar(40)) as cValue) F1
cross apply (select CHARINDEX('.',REVERSE(cValue)) as DecimalPointPos) F2

I think we need to search for 0, not for .