You are indicating that the variable value is a SAS MISSING (or sometimes considered a NULL) value. There is the same precision for such a variable, determined by the SAS LENGTH associated with the variable. If unspecified, the default is SAS numeric length 8 (unless overridden).
Your condition appears to be that your SAS variable is not being computed, so you will want to review your SAS code.
You do not need to identify any maximum precision. The only reason to shorten the SAS LENGTH of a numeric variable would be to conserve disk space -- normally something you need not be concerned about. What you need to be concerned about is what "output format" to use, given your data -- again a default assignment normally satisfies the condition.
Basically I want to migrate this dataset into another database eg.Oracle. So to create a table in Oracle, I should know maximum decimal precision value / attribute definition for that column to migrate this column to Oracle.