Displaying Fields from Multiple Datasets (RS2000)

Hi guys, I have this problem of displaying fields from multiple datasets.

When I drag a field from the first dataset into a table, it works and displayed correctly. However when I dragged a field from a second dataset, it will be shown as

=First(Fields!FirstName.Value, "DataSet2") for Strings and

=Sum(Fields!StatusFlag.Value, "DataSet2") for Integers

I just want the integer from that single row but it sums up all the rows. When I removed the SUM keyword, the IDE will show build errors when I try to build the report. Is there any way to get around this thanks!