怎样按一定时间间隔跳跃查询数据？

问题来自云栖问答，觉得比较好，所以记录一下:

我的项目用的是MySQL，但也想同时请教下在Oracle、SqlServer中应该如何处理如下问题：

有数据表如下所示：
希望从表中抽取数据，要求两条记录的时间间隔至少2分钟
对下面图片中的数据而言，假如我查询的时间范围是从2014-08-10 23:20:00开始的，
则希望抽取到如下结果集：
'83', '57', '10041', '74.27', '0', '2014-08-10 23:20:04'
'113', '57', '10041', '59.25', '0', '2014-08-10 23:22:06'
'145', '57', '10041', '96.21', '0', '2014-08-10 23:24:07'
'177', '57', '10041', '34.16', '0', '2014-08-10 23:26:08'
'209', '57', '10041', '39.11', '0', '2014-08-10 23:28:09'
真实的场景是：传感器每隔30秒左右会向数据库里写一条记录，我要取N天的数据绘图，如果一次性查询N天的记录再进行抽稀的话，由于结果集太大，循环次数过多，导致时耗严重。我希望能通过sql语句直接在数据库层面进行数据抽稀，程序里要处理的数据就会少很多。

问题就是，应该如何写SQL语句？

对于PostgreSQL数据库来说，这个需求很简单，写个函数就可以搞定。
例子：

digoal=# create table test(id serial, crt_time timestamp);
CREATE TABLE
digoal=# insert into test (crt_time) select generate_series(now(),now()+interval '10 min', interval '30 sec');
INSERT 0 21
digoal=# select * from test;
 id |          crt_time          
----+----------------------------
  1 | 2016-04-12 10:25:08.696388
  2 | 2016-04-12 10:25:38.696388
  3 | 2016-04-12 10:26:08.696388
  4 | 2016-04-12 10:26:38.696388
  5 | 2016-04-12 10:27:08.696388
  6 | 2016-04-12 10:27:38.696388
  7 | 2016-04-12 10:28:08.696388
  8 | 2016-04-12 10:28:38.696388
  9 | 2016-04-12 10:29:08.696388
 10 | 2016-04-12 10:29:38.696388
 11 | 2016-04-12 10:30:08.696388
 12 | 2016-04-12 10:30:38.696388
 13 | 2016-04-12 10:31:08.696388
 14 | 2016-04-12 10:31:38.696388
 15 | 2016-04-12 10:32:08.696388
 16 | 2016-04-12 10:32:38.696388
 17 | 2016-04-12 10:33:08.696388
 18 | 2016-04-12 10:33:38.696388
 19 | 2016-04-12 10:34:08.696388
 20 | 2016-04-12 10:34:38.696388
 21 | 2016-04-12 10:35:08.696388
(21 rows)

create or replace function get_sparse_data(b timestamp, e timestamp, sparse interval, lmt int) returns setof test as 
$$

declare
  res test;
  rec test;
  cn int := 0;
begin
  for rec in select * from test where crt_time between b and e order by crt_time loop
    if res is null or rec.crt_time - res.crt_time >= sparse then
      res := rec;
      cn := cn+1;
      return next res;
    end if;

    if cn >= lmt then
      return;
    end if;
  end loop;
end;

$$
 language plpgsql;

digoal=# select get_sparse_data('2016-04-12 10:26:38.696388', '2016-04-12 10:34:08.696388', '1 min', 5);
          get_sparse_data          
-----------------------------------
 (4,"2016-04-12 10:26:38.696388")
 (6,"2016-04-12 10:27:38.696388")
 (8,"2016-04-12 10:28:38.696388")
 (10,"2016-04-12 10:29:38.696388")
 (12,"2016-04-12 10:30:38.696388")
(5 rows)

digoal=# select get_sparse_data('2016-04-12 10:26:38.696388', '2016-04-12 10:34:08.696388', '2 min', 5);
          get_sparse_data          
-----------------------------------
 (4,"2016-04-12 10:26:38.696388")
 (8,"2016-04-12 10:28:38.696388")
 (12,"2016-04-12 10:30:38.696388")
 (16,"2016-04-12 10:32:38.696388")
(4 rows)