CASE WHEN MONTH([date_field]) BETWEEN 1 AND 3 THEN 'Q1' WHEN MONTH([date_field]) BETWEEN 4 AND 6 THEN 'Q2' WHEN MONTH([date_field]) BETWEEN 7 AND 9 THEN 'Q3' WHEN MONTH([date_field]) BETWEEN 10 AND 12 THEN 'Q4' END AS Quarter