These steps assume you're using just the QC user interface. The answer you linked is better if you're looking for code.
See the number of tests in a single test set:
- Navigate to the Test Lab module
- Select a test set in the tree (not a folder).
- In the right-hand pane, select the "Execution Grid" tab
- Look at the bottom of the QC window, near the middle. The number of tests in the test set appears as "Test 1 of xx"
Use Live Analysis to see the number of tests in each test set under the selected folder:
- From the Live Analysis tab, click Add Graph (you may have to remove one first)
- Select Summary and click Next
- Click the Group By drop-down list, and select "Status". Click Next.
- Click the X-Axis drop-down list, and select "Test Set". Click Finish.
The graph should now show all the tests sets at any level under the selected folder. The number shown on the top of each bar is the total number of tests. Mouse over each color in the bar to see how many tests passed or failed in each test set.
You can also select different values in the "Group By" step above to see things like the planning status, priority, test author and so on.