SAP ABAP Message Class AQ Message Number 521 (Table is already being used)
Hierarchy
SAP_BASIS (Software Component) SAP Basis Component
   BC-SRV-QUE (Application Component) SAP Query
     SQUE (Package) Application Development R/3 SAP Query
Attribute
Message class AQ  
Short Description Message texts for SAP Query    
Message Number 521  
Documentation status       Space: object requires documentation
Authorization check Error Message      
Changed On 20090618   
Message Text
Table is already being used
Help Document

Diagnosis

The table you attempted to include in the join already exists. This is not allowed.

System Response

Procedure

History
Last changed on/by 20140121  SAP 
SAP Release Created in