可以使用count和max，因为序列从零开始

select group1
 from my_table 
 group by group1
 having count(*) = max(sequence) +1

最后一句话你可以用

select group1
 from my_table 
 group by group1
 having count(distinct sequence) = max(sequence) +1

如果 sequence 可能有重复的，那你就要小心了。一种方法是取一个实数序列，减去它，并确保差值是连续的：

select group1
from (select t.*,
             (sequence - row_number() over (partition by group1 order by sequence)) as diff
      from t
     ) t
group by group1
having min(diff) = max(diff);

SELECT group1
FROM
    TableName
GROUP BY
    group1
HAVING
    COUNT(*) = MAX(sequence) - MIN(sequence) + 1

如果基于0或正整数，则此操作有效