SSRS Tablix - Each group as group header row

问题

I have a dataset looks like

Now I want to create a report where Dept as a group should be on row header for each group. looks like

I tried adding Dept as a parent group, but it appears on a column not as a header on top of each group.

来源：https://stackoverflow.com/questions/43123665/ssrs-tablix-each-group-as-group-header-row