instruction: count the number of patients whose procedure long title is endoscopic insertion of stent (tube) into bile duct and lab test fluid is pleural?
response: SELECT COUNT(DISTINCT demographic.subject_id) FROM demographic INNER JOIN procedures ON demographic.hadm_id = procedures.hadm_id INNER JOIN lab ON demographic.hadm_id = lab.hadm_id WHERE procedures.long_title = "Endoscopic insertion of stent (tube) into bile duct" AND lab.fluid = "Pleural"