Сортировка значений в группе, включая группу сведений, для табликса
1 On the design surface, click in the tablix data region to select it. The Grouping pane displays the row groups and column groups for the Tablix data region.
2 In the Row Groups pane, right-click the group name, and then click Edit Group.
3 In the Tablix Group dialog box, click Sort.
4 For each sort expression, follow these steps:
1 Click Add.
2 Type or select an expression by which to sort the data.
3 From the Order column drop-down list, choose the sort direction for each expression. A-Z sorts the expression in ascending order. Z-A sorts the expression in descending order.
5 Click OK.
https://docs.microsoft.com/en-us/sql/reporting-services/report-design/sort-data-in-a-data-region-report-builder-and-ssrs