I have two sharepoint list named city and town. I have created two datasets for each list in SQL Repor Builder 3.0 . City dataset has ID and Title columns. Town dataset has ID, City_Id and Title. My purpose is showing cityname and it's towns in same row. I use LookupSet function like this; =Join(LookupSet(Fields!ID.Value, Fields!City_ID.Value, Fields!Title.Value,"Town"), ",") but, it gives just blank field. How I can use LookupSet function. Thanks

Just a thought - can you check to see if the Fields!ID.Value of your City dataset and the Fields!City_ID.Value of your Town dataset have the same datatypes? Please mark correct answers :)

Thanks, it is really good idea. These are not same type. When I create Town list in sharepoint, I created column named "City" lookup to City list. My Town list has Title, City and City:ID columns. City:ID is not Number field. Actually, When I add City:ID field to dataset it converts to City_ID name of it. Probably it converts as a string. Thanks a lot for your answer, but Can you help me more :) How I can add City:ID field as a integer. I can create one more column called CityId as a Number. I can create a workflow that sets the CityId field automacally. But is there any easier way?

Ok, I found the solution. There is the CInt function that converts to integer. =Join(LookupSet(Fields!ID.Value,CInt(Fields!City_ID.Value), Fields!Title.Value,"Town"), ",")