SELECT * FROM HS_SDA3_Streamlet.Encounter WHERE SourceMRN = '12345'
(Replace 12345 with the MRN of the patient you want to list the records of)
But as Robert mentioned, Intersystems does not recommend querying the tables directly. Do you know if you have a separate query environment set up by using the healthshare Mirror funtionality?
The reason they don't recommend querying the live data directly is due to potential performance impact. But ultimately, that decision is up to you.