1. Primary Sorting: Start by sorting your repeat table data based on a primary merge field, that is, Department of the employees.
   
2. Secondary Sorting: After the primary sorting(Department-wise sorting) is applied, you may find it necessary to refine the order of the data further. (Sort by date of joining) This is where "then sort by" comes into play. You can specify a secondary merge field, that is, Date of joining, to sort the data within each department created by the primary sorting.
   

 Steps to sort repeat records:

1. Create a merge template and connect a data source.
   
2. Within your template, insert a repeat table containing the necessary fields. Note that you can choose between a simple repeat, row repeat, or any other type of repeat region.
   
3. Right-click on the field by which you intend to sort your repeat data. From the drop-down menu, select Sort Repeat Records.
   
   
   
   
4. Primary sorting: Next, select the field you wish to sort by. Specify the field type (e.g., text, date, number), and indicate whether you want the data sorted in ascending or descending order.
   
   
   
   
5. Secondary sorting: Specify a secondary merge field(date of joining) in Then by to sort the data within each group created by the primary sorting.
   
   
   
   
6. Click on Sort to initiate the sorting process. Then, preview your merge to ensure that the data is sorted as desired.