How To Fix W8060 - Table action "Append" is only possible for single-level expressions

SAP Error Message - Details

• Message type: E = Error

• Message class: W8 - Workflow: Expressions, data flow

• Message number: 060

• Message text: Table action "Append" is only possible for single-level expressions

What causes this issue?

The table action "Append" (Syntax '//') is only possible, if the
assignment is to a single-level expression.

System Response

The system issues an error message and will not allow you to continue with this transaction until the error is resolved.

How to fix this error?

Error message extract from SAP system. Copyright SAP SE.

Smart SAP Assistant

• What is the cause and solution for SAP error message W8060 - Table action "Append" is only possible for single-level expressions ?

  Certainly! Here's a detailed explanation for the SAP error message:
  
  SAP Error Message:
  W8060 Table action "Append" is only possible for single-level expressions
  
  Cause:
  This warning occurs when you try to use the APPEND statement on a nested/internal table expression rather than on a single-level internal table variable.
  In ABAP, the APPEND statement is designed to add a line to a single-level internal table. If you attempt to append to a nested table or a complex expression (like a component of a structure that is itself a table), the system raises this warning.
  Example causing the error:
  TYPES: BEGIN OF ty_line,
           subtab TYPE TABLE OF string,
         END OF ty_line.
  
  DATA: itab TYPE TABLE OF ty_line,
        wa   TYPE ty_line.
  
  APPEND 'abc' TO wa-subtab.  " This is valid
  APPEND wa-subtab TO itab-subtab. " Invalid, causes W8060
  Or more commonly:
  APPEND wa-subtab TO itab-subtab. " itab-subtab is a nested table component, not a single-level table variable
  
  Explanation:
  
  APPEND expects a single-level internal table variable on the right side.
  You cannot use APPEND on a table expression or a nested table component directly.
  The table you append to must be a standalone internal table variable, not a component or expression.
  
  
  Solution:
  
  
  Use a single-level internal table variable for the APPEND operation.
  
  
  If you want to append to a nested table inside a structure, first assign the nested table to a separate internal table variable, append to it, and then assign it back.
  
  
  Example fix:
  DATA: lt_subtab TYPE TABLE OF string,
        ls_line   TYPE ty_line.
  
  " Copy nested table to a separate variable
  lt_subtab = ls_line-subtab.
  
  " Append to the separate variable
  APPEND 'abc' TO lt_subtab.
  
  " Assign back to the nested table component
  ls_line-subtab = lt_subtab.
  
  Alternatively, if you want to append a line to a nested table inside a structure, you can use the INSERT statement with an index or use the COLLECT statement depending on your use case.
  
  
  Related Information:
  
  ABAP Statements: APPEND, INSERT, COLLECT
  Internal Tables: Single-level vs nested internal tables
  Data Types: Structures containing internal tables
  SAP Notes: Sometimes SAP Notes provide updates or corrections related to internal table handling.
  
  
  Summary:
  
  Cause: Using APPEND on a nested/internal table expression instead of a single-level internal table variable.
  Solution: Use a separate internal table variable for the nested table, append to it, then assign it back.
  Related: Understand the difference between single-level and nested internal tables in ABAP.
  
  
  If you want, I can provide a code snippet tailored to your specific scenario. Just share your code!