Thanks for the good discussion. For the record, I agree with Hugo -- ISNUMERIC doesn't give you very good information because it's test is overly broad.

For example,

\- ,,.,

succeeds in ISNUMERIC() because that converts to a MONEY value of 0.

If you want to see some of the other odd things that are considered numeric by this function, try this:

declare @limit int

set @limit = 4

;with l as (

select 32 as i, char(32) as s, isnumeric(char(32)) as n

union all

select i+1, char(i+1), isnumeric(char(i+1)) from l where i < 127

),

m as (

select cast(l.s as varchar(max)) as ms, isnumeric(l.s) as mn

from l

where ISNUMERIC(l.s) = 1

union all

select ms + cast(l.s as varchar(max)), ISNUMERIC(ms + cast(l.s as varchar(max)))

from m,l

where mn = 1

and datalength(ms) < @limit

and ms not like '%[0-9]%')

select ms from m

where mn = 1 and ms not like '%[0-9]'

option (maxrecursion 0)

This will return all of the strings with length of @limit or below which pass ISNUMERIC() even though they don't contain any digits.