How To Fix DDLS477 - Extension category #GROUP_BY or #UNION requires #PROJECTION_LIST

DDLS477 - Overview

• Message type: E = Error

• Message class: DDLS - For DDL source handling

• Message number: 477

• Message text: Extension category #GROUP_BY or #UNION requires #PROJECTION_LIST

Self-Explanatory Message

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DDLS477 - Details

• The SAP error message DDLS477 indicates that there is an issue with the SQL statement being executed, specifically related to the use of the GROUP BY or UNION clauses without a proper PROJECTION_LIST. This error typically arises in the context of ABAP Dictionary or when working with Open SQL in ABAP programs.
  
  Cause:
  The error occurs when:
  
  You are using a GROUP BY clause without specifying the necessary fields in the SELECT statement.
  You are using a UNION operation without ensuring that the result sets being combined have the same structure (i.e., the same number of columns and compatible data types).
  The SQL statement does not include a projection list that defines which fields to select, which is required when using aggregation functions or combining result sets.
  
  
  Solution:
  To resolve the DDLS477 error, you can take the following steps:
  
  
  Check the SELECT Statement:
  
  Ensure that your SELECT statement includes a projection list that specifies the fields you want to