1、删除序列
--删除序列，如果存在则删除，如果不判断会报错
declare
num number;
begin
select count（1） into num from user_sequences where sequence_name= 'SQ_Name';
if num=1 then
execute immediate 'drop SEQUENCE SQ_Name';
end if;
end;
2、创建序列
DECLARE
s_ID NUMBER;
BEGIN
select MAX(RECID)+1 into s_ID from S_TableName;--序列起始号获得，某列的最大值+1
EXECUTE immediate 'create sequence SQ_SequName minvalue 1 maxvalue 9999999999999999999999999999 start with '||s_ID||'increment by 1 cache 200';
END;