How To Fix DD_CDS_ANALYSIS252 - $$projection cannot be used as an alias

SAP Error Message - Details

• Message type: E = Error

• Message class: DD_CDS_ANALYSIS - CDS code inspector messages

• Message number: 252

• Message text: $$projection cannot be used as an alias

What causes this issue?

"$projection" is not allowed as an alias

How to fix this error?

Choose a different alias name

Error message extract from SAP system. Copyright SAP SE.

Smart SAP Assistant

• What is the cause and solution for SAP error message DD_CDS_ANALYSIS252 - $$projection cannot be used as an alias ?

  The SAP error message DD_CDS_ANALYSIS252 with the description $$projection cannot be used as an alias typically occurs in the context of Core Data Services (CDS) views in SAP HANA or ABAP CDS. This error indicates that there is an issue with how projections (or aliases) are being defined in your CDS view.
  Cause:
  The error arises when you attempt to use a projection (which is a way to select specific fields from a data source) as an alias in your CDS view definition. In CDS, projections are meant to define the structure of the data being selected, and they cannot be used interchangeably with aliases.
  Solution:
  To resolve this error, you should check your CDS view definition for the following:
  
  
  Review the Projection Definition: Ensure that you are not trying to use a projection as an alias. Instead, define your projections clearly and use them appropriately in your SELECT statement.
  
  
  Correct Alias Usage: If you need to use an alias, make sure you are using it correctly. An alias should be a simple name that refers to a field or a table, not a projection.
  
  
  Check Syntax: Ensure that your CDS view syntax is correct. Look for any misplaced keywords or incorrect usage of projections and aliases.
  
  
  Example Correction:
  If you have something like this:
  define view my_view as
  select from my_table
  {
      field1,
      field2 as $$projection
  }
  You should change it to:
  define view my_view as
  select from my_table
  {
      field1,
      field2
  }
  
  
  Documentation: Refer to the official SAP documentation for Core Data Services to understand the correct usage of projections and aliases.
  
  
  Related Information:
  
  CDS Views: Core Data Services (CDS) are a way to define semantic data models in SAP. They allow for the definition of views on database tables with a focus on business semantics.
  SAP HANA: If you are using SAP HANA, ensure that you are familiar with its SQL dialect and how it handles projections and aliases.
  SAP Notes: Check for any relevant SAP Notes or Knowledge Base Articles that might provide additional context or updates regarding this error.
  
  By following these steps, you should be able to resolve the error and correctly define your CDS view.