How To Fix RSRTS_CDS169 - Alias &1: nesting CAST expressions is not supported

SAP Error Message - Details

• Message type: E = Error

• Message class: RSRTS_CDS - Messages Transient CDS Queries

• Message number: 169

• Message text: Alias &1: nesting CAST expressions is not supported

Self-Explanatory Message

Since SAP believes that this specific error message is 'self-explanatory,' no more information has been given.The majority of messages in the SAP system have a message text, however this is frequently insufficient to comprehend or resolve the problem.

To make things easier, more detailed information is frequently added to describe the issue, how to fix it, and the necessary steps or configuration modifications.

Unfortunately, there isn't any extra information in this error notice.

What else can you do?

First, use our AnswerBot below to get a possible cause and solution (requires a premium subscription).

Also, review the in-depth Common Questions & Answers listed below; you could discover a solution there or be able to connect with others who have faced similar challenges.

You can also try searching the SAP support portal (support.sap.com) but you need a special user ID to access it. It is possible that an SAP support note exists that provides additional details about the mistake or even steps for fixing it.

Smart SAP Assistant

• What is the cause and solution for SAP error message RSRTS_CDS169 - Alias &1: nesting CAST expressions is not supported ?

  The SAP error message RSRTS_CDS169 indicates that there is an issue with the use of nested CAST expressions in a Core Data Services (CDS) view or query. This error typically arises when you are trying to convert data types in a way that is not supported by the underlying database or the CDS framework.
  Cause
  The error occurs when:
  
  You have a CDS view or a query that includes multiple CAST operations nested within each other. For example, you might be trying to cast a field to one type and then immediately cast that result to another type.
  The database engine does not support this kind of nested casting, which can lead to ambiguity or complexity in the execution plan.
  
  Solution
  To resolve the error, you can take the following steps:
  
  
  Flatten the CAST Operations: Instead of nesting CAST operations, try to simplify your expressions. For example, if you have:
  CAST(CAST(field AS type1) AS type2)
  You should first cast to type1 and store it in a temporary variable or a separate field, and then cast that result to type2.
  
  
  Check Data Types: Ensure that the data types you are trying to cast to and from are compatible. Sometimes, you may not need to cast at all if the types are already compatible.
  
  
  Use Intermediate Variables: If you need to perform multiple transformations, consider breaking them down into separate steps or using intermediate variables to hold the results of each cast.
  
  
  Review the CDS View Definition: If you are working with a CDS view, review its definition to ensure that the data types are correctly defined and that you are not inadvertently introducing nested casts.
  
  
  Test in Isolation: If possible, isolate the problematic part of your query or view and test it separately to identify the exact location of the issue.
  
  
  Related Information
  
  SAP Documentation: Refer to the official SAP documentation for Core Data Services (CDS) to understand the limitations and best practices regarding data type conversions.
  SAP Community: Engage with the SAP Community forums where other users may have encountered similar issues and can provide insights or solutions.
  Database Documentation: Depending on the database you are using (e.g., HANA, SQL Server), check the specific documentation for that database regarding type casting and supported operations.
  
  By following these steps, you should be able to resolve the RSRTS_CDS169 error and successfully execute your CDS view or query.