instruction: how many patients are diagnosed with hx of colonic malignancy and have iv route of drug administration?
response: SELECT COUNT(DISTINCT demographic.subject_id) FROM demographic INNER JOIN diagnoses ON demographic.hadm_id = diagnoses.hadm_id INNER JOIN prescriptions ON demographic.hadm_id = prescriptions.hadm_id WHERE diagnoses.short_title = "Hx of colonic malignancy" AND prescriptions.route = "IV"