I have RDLC Tablix which has data below. My table is grouped by 1st column.

the red highlighted column shows the join value comma separated with respected to the 1st column. However there is repeating 1,1 in 1st row.

Main data set looks like something below

Question:

• How to avoid the repeating value in join statement. following is the textbox expression I have tried now

=Join(LookUpSet(Fields!Col1.Value, Fields!Col1.Value, Fields!Col3.Value, "DSName"), ",")