How To Fix SDDL_PARSER_MSG475 - UNION cannot be used in extends on projection views

SAP Error Message - Details

• Message type: E = Error

• Message class: SDDL_PARSER_MSG - Message Class for DDL Parser

• Message number: 475

• Message text: UNION cannot be used in extends on projection views

Self-Explanatory Message

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Smart SAP Assistant

• What is the cause and solution for SAP error message SDDL_PARSER_MSG475 - UNION cannot be used in extends on projection views ?

  The SAP error message SDDL_PARSER_MSG475 indicates that there is an issue with the use of the UNION operator in the context of projection views in SAP HANA. This error typically arises when you attempt to create a projection view that uses a UNION operation in a way that is not supported by the projection view's definition.
  Cause:
  The error occurs because projection views in SAP HANA are designed to represent a single, unified view of data from one or more tables or other views. However, the use of UNION in the context of projection views is not allowed. Projection views are meant to project specific columns from a single source or a set of sources without combining rows from multiple sources using UNION.
  Solution:
  To resolve this error, you can consider the following approaches:
  
  
  Avoid Using UNION in Projection Views:
  
  Instead of trying to use UNION within a projection view, create separate views for each of the datasets you want to combine. You can then create a separate view that uses UNION to combine the results of those projection views.
  
  
  
  Use Calculation Views:
  
  If you need to combine data from multiple sources using UNION, consider using a calculation view instead of a projection view. Calculation views support more complex logic, including the use of UNION, and can be used to create a more flexible data model.
  
  
  
  Check View Definitions:
  
  Review the definitions of your views to ensure that you are not inadvertently trying to use UNION in a projection view. Make sure that the logic aligns with the intended use of projection views.
  
  
  
  Refactor Your Query:
  
  If you are writing a SQL query that involves a projection view, refactor the query to avoid using UNION directly in the projection view context.
  
  
  
  Related Information:
  
  Projection Views: These are used to select specific columns from a single table or view. They are lightweight and optimized for performance.
  Calculation Views: These are more complex and can include various operations such as joins, unions, and aggregations. They are suitable for scenarios where you need to combine data from multiple sources.
  SAP HANA Documentation: For more detailed information on the differences between projection views and calculation views, refer to the official SAP HANA documentation.
  
  By following these guidelines, you should be able to resolve the error and design your views appropriately in SAP HANA.