When you perform concatenation or mixed-mode arithmetic on values with different
datatypes, the SAP ASE server must determine the datatype, length, and precision of the
result.
Determine the Datatype Hierarchy
Each system datatype has a datatype hierarchy, which is stored in the systypes system table. User-defined datatypes inherit the hierarchy of the system datatype on which they are based.
Determine Precision and Scale
For numeric and decimal datatypes, each combination of precision and scale is a distinct SAP ASE datatype.