最佳答案
                                        
                                                                        
                                I'm getting the following error in SSRS:
An error occurred while the query design method was being saved.
An item with the same key has already been added
What does an "item" denote, though? I even tried editing the RDL and deleting all references to  the Stored Procedure I need to use called prc_RPT_Select_BI_Completes_Data_View.
Could this possibly have to do with the fact that the Stored Procedure uses Dynamic SQL (the N'  notation)?
In the stored procedure I have:
SET @SQL +=  N'
SELECT   bi.SupplierID as ''Supplier ID''
,bi.SupplierName as ''Supplier Name''
,bi.PID as ''PID''
,bi.RespondentID as ''Respondent ID''
,lk_slt.Name as ''Entry Link Type''
,ts.SurveyNumber as ''Initial Survey ID'''
