What is the difference between the number of married patients and the number of single patients with diabetes?
difference = SUBTRACT(patients.patient WHERE marital = 'M'), COUNT(patients.patient WHERE marital = 'S') WHERE conditions.DESCRIPTION = 'Diabetes'); married patients refers to marital = 'M'; single patients refers to marital = 'S'; diabetes refers to conditions.DESCRIPTION = 'Diabetes';
SELECT SUM(CASE WHEN T2.marital = 'M' THEN 1 ELSE 0 END) - SUM(CASE WHEN T2.marital = 'S' THEN 1 ELSE 0 END) FROM conditions AS T1 INNER JOIN patients AS T2 ON T1.PATIENT = T2.patient WHERE T1.DESCRIPTION = 'Diabetes'