16.10 - Example: Comparing Floating Point Values - Teradata Database

Teradata Database SQL Data Types and Literals

prodname
Teradata Database
vrm_release
16.10
created_date
June 2017
category
Programming Reference
featnum
B035-1143-161K

Calculations involving floating point values often produce results that are not what you expect. If you perform a floating point calculation and then compare the results against some expected value, it is unlikely that you get the intended result. Consider the results of Example: Non-Associativity of Floating Point Arithmetic.

Instead of comparing the results of a floating point calculation, make sure that the result is greater or less than what is needed, with a given error. Here is an example of how to rewrite the statement in Example: Non-Associativity of Floating Point Arithmetic and achieve the desired results:

   SELECT i, SUM(a) as sum_a, SUM(b) as sum_b
   FROM t1
   GROUP BY i
   HAVING ABS(sum_a - sum_b) > 1E-10;