Chapter 1: System and User-Defined Datatypes

Determining precision and scale

For numeric and decimal datatypes, each combination of precision and scale is a distinct Adaptive Server datatype. If you perform arithmetic on two numeric or decimal values:

n1 with precision p1 and scale s1, and
n2 with precision p2 and scale n2

Adaptive Server determines the precision and scale of the results as shown in Table 1-3.

**Table 1-3: Precision and scale after arithmetic operations**
Operation	Precision	Scale
n1 + n2	max(s1, s2) + max(p1 -s1, p2 - s2) + 1	max(s1, s2)
n1 - n2	max(s1, s2) + max(p1 -s1, p2 - s2) + 1	max(s1, s2)
n1 * n2	s1 + s2 + (p1 - s1) + (p2 - s2) + 1	s1 + s2
n1 / n2	max(s1 + p2 + 1, 6) + p1 - s1 + p2	max(s1 + p2 -s2 + 1, 6)

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