How To Fix 37809 - Fixed step loop not allowed next to a variable (step loop unchanged)

SAP Error Message - Details

• Message type: E = Error

• Message class: 37 - Screen Painter

• Message number: 809

• Message text: Fixed step loop not allowed next to a variable (step loop unchanged)

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Smart SAP Assistant

• What is the cause and solution for SAP error message 37809 - Fixed step loop not allowed next to a variable (step loop unchanged) ?

  The SAP error message 37809, "Fixed step loop not allowed next to a variable (step loop unchanged)," typically occurs in ABAP programming when there is an issue with the structure of your loop statements, particularly when using nested loops or when defining step loops in a way that is not allowed by the ABAP language rules.
  Cause:
  This error arises when you have a fixed step loop (using LOOP AT ... INTO ...) that is incorrectly placed next to a variable step loop (using LOOP AT ... without a fixed step). In ABAP, you cannot have a fixed step loop immediately followed by a variable step loop without proper separation or structure. This is because the ABAP runtime expects a specific structure for loops, and mixing these types can lead to ambiguity in how the data is processed.
  Solution:
  To resolve this error, you need to ensure that your loop structures are correctly defined. Here are some steps you can take:
  
  
  Check Loop Definitions: Review your loop definitions to ensure that you are not mixing fixed and variable step loops. If you have a fixed step loop, ensure that it is not immediately followed by a variable step loop without proper separation.
  
  
  Use Nested Loops Properly: If you need to use both types of loops, consider restructuring your code. For example, you can use nested loops but ensure that the outer loop is a variable step loop if the inner loop is a fixed step loop.
  
  
  Separate Loops: If you have a fixed step loop followed by a variable step loop, consider separating them with a clear block of code or restructuring the logic to avoid this situation.
  
  
  Review Documentation: Consult the ABAP documentation for more details on loop structures and best practices to avoid such errors.
  
  
  Example:
  Here’s a simple example to illustrate the issue:
  DATA: lt_data TYPE TABLE OF string,
        lv_string TYPE string.
  
  LOOP AT lt_data INTO lv_string. " Variable step loop
    " Some processing
    LOOP AT lt_data INTO lv_string. " This will cause error 37809
      " Some processing
    ENDLOOP.
  ENDLOOP.
  In the above example, the inner loop is a variable step loop immediately following another variable step loop. To fix this, you could restructure it as follows:
  DATA: lt_data TYPE TABLE OF string,
        lv_string TYPE string.
  
  LOOP AT lt_data INTO lv_string. " Outer loop
    " Some processing
  ENDLOOP.
  
  LOOP AT lt_data INTO lv_string. " Separate variable step loop
    " Some processing
  ENDLOOP.
  Related Information:
  
  ABAP Documentation: Refer to the official SAP ABAP documentation for detailed information on loop constructs and their usage.
  SAP Community: Engage with the SAP Community forums for discussions and solutions related to specific ABAP errors.
  Debugging: Use the ABAP debugger to step through your code and identify where the loop structure is causing issues.
  
  By following these guidelines, you should be able to resolve the error and ensure your ABAP code adheres to the required structure.