Which physicians prescribe a medication of brand X? Tell me the name and position of those physicians.
SELECT DISTINCT T1.name ,  T1.position FROM physician AS T1 JOIN prescribes AS T2 ON T1.employeeid = T2.physician JOIN medication AS T3 ON T3.code = T2.medication WHERE T3.Brand  =  "X"
physicians who prescribe a specific medication refers to JOIN between physician, prescribes, and medication tables; medication of brand X refers to WHERE condition on medication.Brand; name and position of those physicians refers to SELECTING name and position columns from physician table;