oracle 根据数值范围分组

SELECT grp, COUNT(1)
FROM (
    SELECT CASE 
            WHEN value < 3 THEN 'LessThan3'
            WHEN value >= 3
            AND value < 5 THEN '3_5'
            WHEN value >= 5 THEN 'GreaterThan5'
            ELSE 'null'
        END AS grp
    FROM table
)
GROUP BY grp;