Message type: E = Error
Message class:  RS2HANA_VIEW - HANA Views for BW Objects 
Message number: 081
Message text: External SAP HANA view: Variable has no default value
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.
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.
The SAP error message RS2HANA_VIEW081 indicates that an external SAP HANA view has a variable that does not have a default value assigned. This can occur when you are trying to execute a query or report that relies on a HANA view, and one or more of the variables required for the execution are not provided with default values.
Cause: Missing Default Value: The variable in the HANA view is defined without a default value, and the query execution requires this variable to be populated. Variable Configuration: The variable may be configured to require user input at runtime, but if the system is not set up to provide a default, it leads to this error. Data Source Changes: If the underlying data source or the structure of the HANA view has changed, it may affect how variables are handled.
Solution: Assign Default Values: Go to the HANA view in the SAP HANA Studio or Web IDE. Locate the
 Get instant SAP help. Sign up for our Free Essentials Plan.
Get instant SAP help. Sign up for our Free Essentials Plan. 
RS2HANA_VIEW080 External SAP HANA view: Variable representation 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...
RS2HANA_VIEW079 External SAP HANA view: "Processing By" type 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...
RS2HANA_VIEW082 External SAP HANA view: Time reference field 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...
RS2HANA_VIEW083 External SAP HANA view: Time shift 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...
Click on this link to search all SAP messages.