In SSRS, why do I get the error "item with same key has already been added" , when I'm making a new report?

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'''

enter image description here

Solution 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.

Solution 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.

Solution 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

Solution 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)

Solution 5:

Sorry, it is a response to an old thread, but might still be useful.

In addition to above responses, This generally 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.