How To Fix DDLS171 - After CASE, currently only a table column is allowed

SAP Error Message - Details

• Message type: E = Error

• Message class: DDLS - For DDL source handling

• Message number: 171

• Message text: After CASE, currently only a table column is allowed

Self-Explanatory Message

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Smart SAP Assistant

• What is the cause and solution for SAP error message DDLS171 - After CASE, currently only a table column is allowed ?

  The SAP error message DDLS171 typically occurs when you are trying to use a CASE statement in a SQL query or a data definition language (DDL) statement in a way that is not supported by the SAP database. The error indicates that the CASE statement is being used incorrectly, and currently, only a table column is allowed in that context.
  Cause:
  The error arises from the following scenarios:
  
  Incorrect Usage of CASE: The CASE statement is being used in a context where it is not allowed, such as in a DDL statement or in a way that does not conform to the expected syntax.
  Database Compatibility: The specific database you are using (e.g., HANA, Oracle, etc.) may have limitations on how CASE statements can be used, especially in DDL contexts.
  Syntax Errors: There may be syntax errors in the SQL statement that lead to this error being triggered.
  
  Solution:
  To resolve the error, consider the following steps:
  
  
  Review the SQL Statement: Check the SQL statement where the CASE is being used. Ensure that it is being used in a valid context, such as within a SELECT statement rather than a DDL statement.
  Example of correct usage in a SELECT statement:
  SELECT 
      CASE 
          WHEN condition1 THEN result1
          WHEN condition2 THEN result2
          ELSE result_default
      END AS alias_name
  FROM table_name;
  
  
  Use CASE in Allowed Contexts: Ensure that you are using the CASE statement only in contexts where it is allowed, such as in SELECT, WHERE, or ORDER BY clauses.
  
  
  Check Database Documentation: Refer to the documentation for the specific database you are using to understand the limitations and correct usage of the CASE statement.
  
  
  Simplify the Query: If the CASE statement is complex, try simplifying it or breaking it down into smaller parts to identify the issue.
  
  
  Testing: Test the SQL statement in a SQL console or editor to see if it executes without errors. This can help isolate the problem.
  
  
  Related Information:
  
  SAP Notes: Check SAP Notes for any known issues or updates related to this error message.
  Database Documentation: Review the documentation for the specific database you are using (e.g., SAP HANA SQL Reference) for details on the CASE statement and its usage.
  Community Forums: Look for discussions in SAP Community forums or other technical forums where similar issues may have been addressed.
  
  By following these steps, you should be able to identify the cause of the DDLS171 error and implement a solution to resolve it.