您可以使用ALTER SEQUENCE语法。
Tom Kyte在这里解释了如何做到这一点：
http://asktom.oracle.com/pls/asktom/f?p=100:11:0::::P11_QUESTION_ID:1119633817597

只需删除并重新创建序列。

这就是我重置它的方法

CREATE OR REPLACE PROCEDURE reset_sequence (
   p_sequence_name   IN   VARCHAR2,
   p_new_value       IN   NUMBER
)
AS
   l_current_value     NUMBER;
   v_sequence_exists   NUMBER;
BEGIN
   SELECT 1
   INTO   v_sequence_exists
   FROM   user_sequences
   WHERE  sequence_name = p_sequence_name;

   EXECUTE IMMEDIATE 'SELECT ' || p_sequence_name || '.nextval FROM dual'
   INTO              l_current_value;

   /*Not possible to increment by 0 !*/
   IF (p_new_value - l_current_value - 1) != 0
   THEN
      EXECUTE IMMEDIATE    'ALTER SEQUENCE '
                        || p_sequence_name
                        || ' INCREMENT BY '
                        || (p_new_value - l_current_value - 1)
                        || ' MINVALUE 0';
   END IF;

   EXECUTE IMMEDIATE 'SELECT ' || p_sequence_name || '.nextval FROM dual'
   INTO              l_current_value;

   EXECUTE IMMEDIATE 'ALTER SEQUENCE ' || p_sequence_name || ' INCREMENT BY 1 ';
EXCEPTION
   WHEN NO_DATA_FOUND
   THEN
      raise_application_error (-20001, 'Sequence does not exist');
END;

与删除和重新创建相比，这有一个额外的好处，即不会使任何相关的模式对象失效。

试试这个

alter table "table_name"
modify "id" generated always as identity restart start with 1;