Message type: E = Error
Message class:  CNV_00001 - Message class for CWB settings maintenance programs 
Message number: 245
Message text: Aggregation type specified for non-aggregated field &1 of table &2
Field &V1& of table &V2& has the aggregation type set although the
conversion scenario for table &V2& doesn't involve aggregation of field
values.
Status is set to 'Warning'.
Remove aggregation type specification for field &V1& of table &V2& or
change the duplicate processing type to 'G' (aggregation of selected
fields) or 'P' (priority - it also allows aggregation of selected
fields)
The system issues an error message and will not allow you to continue with this transaction until the error is resolved.
Error message extract from SAP system. Copyright SAP SE.
The SAP error message CNV_00001245 indicates that there is an issue with the aggregation type specified for a non-aggregated field in a table during a data conversion or migration process. This error typically arises in the context of SAP's data migration tools, such as the SAP S/4HANA Migration Cockpit or other data transformation processes.
Cause: The error occurs when: An aggregation type (like SUM, AVG, COUNT, etc.) is incorrectly assigned to a field that is not designed to be aggregated. The field in question is likely a detail or transactional field that does not support aggregation, meaning it should be treated as a single value rather than a summary statistic.
Solution: To resolve this error, you can take the following steps: Identify the Field and Table: Check the error message for the specific field (&1) and table (&2) that is causing the issue. Review the Data Mapping: Look at the data mapping or transformation rules you
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