Hugo Kornelis (5/26/2010)
The difference will never be more than 0.0001, which admittedly is not significant in most cases. But in those cases where that difference is important, the difference between "60.0" and "CAST(60 AS numeric(10,4))" does matter.
If you really want accuracy, don't you have to use CAST(60 as numeric(10,5)) to keep the error below 0.00006? Using CAST(60 as numeric(10,4)) does the division and truncates the result; subsequently that is rounded but this has no effect as it's rounding a numeric(10,4) value to numeric(10,4). (Another reason to dislike SQL's approach to type conversion, truncation, and rounding for expressions on the RHS of assignments.)
Tom