摘要: 1. SQL> select * from x; A 1 2 3 5 SQL> select a as snaped,lag(a, 2) OVER(ORDER BY a) as snapst from x; SNAPED SNAPST 1 2 3 1 5 2 SQL> sample 2: SQL> 阅读全文
posted @ 2017-09-05 14:38 feiyun8616 阅读(5869) 评论(0) 推荐(0) 编辑