How To Fix GS123 - Multiset &1: Field &2 exists more than once

SAP Error Message - Details

• Message type: E = Error

• Message class: GS - Sets

• Message number: 123

• Message text: Multiset &1: Field &2 exists more than once

What causes this issue?

The <DS:GLOS.3526BA3DAFAB52B9E10000009B38F974>multiset</> &V1& contains
more than one set or variable created for the &V2& field. A field (or
characteristic) can, however, only exist once in a multiset.

How to fix this error?

Change the multiset in transaction <DS:TRAN.GS02>GS02</>.
If this error occurs when you import a transport request, check the
multiset in the source system of the transport.
If the set does not contain multiple fields there, you need to
transport the multiset with its objects to remove the error.
If the set also contains errors there, change the multiset in the
source system of the transport then run another transport.

Error message extract from SAP system. Copyright SAP SE.

Smart SAP Assistant

• What is the cause and solution for SAP error message GS123 - Multiset &1: Field &2 exists more than once ?

  The SAP error message GS123 "Multiset &1: Field &2 exists more than once" typically occurs in the context of data processing, particularly when dealing with database tables or structures that are expected to have unique field names. This error indicates that there is a conflict where a field is defined multiple times within a multiset or a data structure.
  Cause:
  
  Duplicate Field Definitions: The most common cause of this error is that the same field name is defined more than once in a multiset or data structure. This can happen if the data model is incorrectly designed or if there are issues in the data extraction or transformation process.
  Incorrect Data Mapping: If you are mapping fields from one structure to another, you might inadvertently map the same source field to multiple target fields.
  Program Logic Errors: In custom ABAP programs, logic errors can lead to the same field being added multiple times to a data structure or internal table.
  
  Solution:
  
  Check Field Definitions: Review the definitions of the multiset or data structure in question. Ensure that each field is defined only once. If you find duplicates, remove or rename them as necessary.
  Review Data Mapping: If you are working with data extraction or transformation, check the mapping logic to ensure that each field is only mapped once.
  Debugging: If the error occurs in a custom program, use the ABAP debugger to trace the execution and identify where the duplicate field is being added. Look for loops or conditions that might be causing the duplication.
  Consult Documentation: If you are using standard SAP functionality, refer to the relevant SAP documentation or notes for guidance on the specific multiset or data structure you are working with.
  
  Related Information:
  
  SAP Notes: Check SAP Notes for any known issues or patches related to this error message. Sometimes, there may be specific fixes or recommendations provided by SAP.
  Data Dictionary: Familiarize yourself with the Data Dictionary (SE11) to understand how tables and structures are defined in your SAP system.
  ABAP Development: If you are a developer, ensure that you follow best practices for defining data structures and avoid naming conflicts.
  
  By addressing the root cause of the duplicate field definitions, you should be able to resolve the GS123 error and proceed with your data processing tasks.