SQL IsNumeric not working

Question

The reserve column is a varchar, to perform sums on it I want to cast it to a deciaml. But the SQL below gives me an error

select
cast(Reserve as decimal)
fr         


        

Answer 1

isnumeric is not 100% reliable in SQL - see this question Why does ISNUMERIC('.') return 1?

I would guess that you have value in the reserve column that passes the isnumeric test but will not cast to decimal.