question

You can use the getcensus() command to get the current patient census in the whole model. You can also pass in a location group to get the census within that location group:

getcensus(Group("ExamTables"))

If you want to get the census of patients with a certain label value you'd need to query the Census History table with a query like this one that returns the census of patients with a PCI label of 2:

string query = "SELECT \
SUM([CensusHistory.StatisticsCollector].[InOut]) \
FROM[CensusHistory.StatisticsCollector]\
JOIN[PersonLabels.StatisticsCollector] ON [PersonLabels.StatisticsCollector].[PID] = [CensusHistory.StatisticsCollector].[PID]\
WHERE[PersonLabels.StatisticsCollector].[PCI] = 2";

Table result = Table.query(query);
if (result.numRows > 0)
    return result.executeCell(1,1);
else
    return 0;