How To Fix AQQIS_CNTRL020 - Illegal left-outer-join chain between tabkes &1,&2 and &3

SAP Error Message - Details

• Message type: E = Error

• Message class: AQQIS_CNTRL - Join-Control InfoSet

• Message number: 020

• Message text: Illegal left-outer-join chain between tabkes &1,&2 and &3

Self-Explanatory Message

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Smart SAP Assistant

• What is the cause and solution for SAP error message AQQIS_CNTRL020 - Illegal left-outer-join chain between tabkes &1,&2 and &3 ?

  The SAP error message AQQIS_CNTRL020 indicates that there is an illegal left outer join chain between the specified tables in your query. This typically occurs when the join conditions between the tables are not properly defined or when the join logic violates the rules of SQL joins.
  Cause:
  
  Improper Join Conditions: The join conditions between the tables may not be correctly defined, leading to an invalid join chain.
  Circular References: There may be circular references in the join conditions, which can create ambiguity in the join logic.
  Incompatible Data Types: The fields being joined may have incompatible data types, which can lead to issues in the join operation.
  Database Constraints: The underlying database may have constraints that prevent the join from being executed as defined.
  
  Solution:
  
  Review Join Conditions: Check the join conditions between the tables involved in the query. Ensure that they are correctly defined and that they logically connect the tables.
  Check for Circular References: Ensure that there are no circular references in the join conditions. If there are, you may need to restructure your query to eliminate them.
  Verify Data Types: Ensure that the fields being joined have compatible data types. If necessary, you may need to cast or convert the data types to make them compatible.
  Simplify the Query: If the query is complex, try simplifying it by breaking it down into smaller parts or using subqueries to isolate the problematic join.
  Use Inner Joins: If possible, consider using inner joins instead of left outer joins, as they may avoid the issues related to outer joins.
  Check Database Documentation: Refer to the database documentation for any specific constraints or limitations regarding joins that may apply to your situation.
  
  Related Information:
  
  SAP Notes: Check SAP Notes for any known issues or patches related to this error message. SAP frequently updates its knowledge base with solutions to common problems.
  SQL Syntax: Familiarize yourself with SQL syntax and join operations to better understand how to structure your queries.
  Performance Considerations: Be aware that complex joins can impact performance. Optimize your queries for better performance if necessary.
  
  If the issue persists after trying the above solutions, consider reaching out to your SAP support team or consulting with a database administrator for further assistance.