问题
I'm getting the following error in SSRS, and it's been puzzling me a while now:
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)?
By the mornin, 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'''
回答1:
It appears that SSRS has an issue(at leastin version 2008) - I'm studying this website that explains it
Where it says if you have two columns(from 2 diff. tables) with the same name, then it'll cause that problem.
From source:
SELECT a.Field1, a.Field2, a.Field3, b.Field1, b.field99 FROM TableA a JOIN TableB b on a.Field1 = b.Field1
SQL handled it just fine, since I had prefixed each with an alias (table) name. But SSRS uses only the column name as the key, not table + column, so it was choking.
The fix was easy, either rename the second column, i.e. b.Field1 AS Field01 or just omit the field all together, which is what I did.
回答2:
I have experience this issue in past. Based on that I can say that generally we get this issue if your dataset has multiple fieldnames that points to same field source. Take a look into following posts for detail error description
http://www.bi-rootdata.com/2012/09/an-error-occurred-during-report.html
http://www.bi-rootdata.com/2012/09/an-item-with-same-key-has-already-been.html
In your case, you should check your all field names returned by Sp prc_RPT_Select_BI_Completes_Data_View and make sure that all fields has unique name.
回答3:
I face the same issue. After debug I fixed the same. if the column name in your sql query has multiple times then this issue occur. Hence use alias in sql query to differ the column name. Ex: The below query will work proper in sql query but create issue in SSRS report:
Select P.ID, P.FirstName, P.LastName, D.ID, D.City, D.Area, D.Address From PersonalDetails P Left Join CommunicationDetails D On P.ID = D.PersonalDetailsID
Reason : ID has mentioned twice (Multiple Times)
Correct Query:
Select P.ID As PersonalDetailsID, P.FirstName, P.LastName, D.ID, D.City, D.Area, D.Address From PersonalDetails P Left Join CommunicationDetails D On P.ID = D.PersonalDetailsID
回答4:
I had the same error in a report query. I had columns from different tables with the same name and the prefix for each table (eg: select a.description, b.description, c.description) that runs ok in Oracle, but for the report you must have an unique alias for each column so simply add alias to the fields with the same name (select a.description a_description, b.description b_description and so on)
回答5:
I just got this error and i came to know that it is about the local variable alias
at the end of the stored procedure i had like
select @localvariable1,@localvariable2
it was working fine in sql but when i ran this in ssrs it was always throwing error but after I gave alias it is fixed
select @localvariable1 as A,@localvariable2 as B
回答6:
Sorry, it is a reponse to an old thread, but might still be usefull.
In addition to above reponses, This genrally happens when two columns with same name, even from different tables are included in the same query. for example if we joining two tables city and state where tables have column name e.g. city.name and state.name. when such a query is added to the dataset, ssrs removes the table name or the table alias and only keeps the name, whih eventually appears twice in the query and errors as duplicate key. The best way to avoid it is to use alias such as calling the column names city.name as c_name state.name as s_name. This will resolve the issue.
来源：https://stackoverflow.com/questions/14466874/in-ssrs-why-do-i-get-the-error-item-with-same-key-has-already-been-added-wh