How To Fix AQQIS_CNTRL021 - &1 cannot be connected to two tables using left-outer join

AQQIS_CNTRL021 - Overview

• Message type: E = Error

• Message class: AQQIS_CNTRL - Join-Control InfoSet

• Message number: 021

• Message text: &1 cannot be connected to two tables using left-outer join

What causes this issue?

The system tried to insert a join or convert a join into a left-outer
join.
The definition would lead to a join condition that does not support
ABAP-SQL at the moment:
The right-hand table would be connected with more than one table across
a left-outer join.
This is not allowed.

System Response

The change was undone.

How to fix this error?

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

Procedure for System Administrators

Error message extract from SAP system. Copyright SAP SE.

AQQIS_CNTRL021 - Details

• The SAP error message AQQIS_CNTRL021 indicates that there is an issue with a query that attempts to connect two tables using a left outer join, but the system is unable to do so due to certain constraints or configurations. This error typically arises in the context of SAP BW (Business Warehouse) or SAP HANA when working with queries or data models.
  
  Cause:
  
  
  Incompatible Join Conditions: The tables you are trying to join may not have compatible join conditions. For a left outer join to work, there must be a valid relationship defined between the two tables.
  
  
  Data Model Configuration: The data model may not be set up correctly. For example, if the tables are not part of the same InfoProvider or if the join conditions are not properly defined in the data model.
  
  
  Cardinality Issues: The cardinality of the relationship between the two tables may not support a left outer join. For instance, if