条带化PostgreSQL结果集的顺序
发布时间:2020-12-13 16:17:56 所属栏目:百科 来源:网络整理
导读:假设我有下表: create temp table test (id serial,number integer);insert into test (number) values (5),(4),(3),(2),(1),(0); 如果按数字降序排序,我得到: select * from test order by number desc;id | number---+-------- 1 | 5 2 | 4 3 | 3 4 | 2
假设我有下表:
create temp table test (id serial,number integer); insert into test (number) values (5),(4),(3),(2),(1),(0); 如果按数字降序排序,我得到: select * from test order by number desc; id | number ---+-------- 1 | 5 2 | 4 3 | 3 4 | 2 5 | 1 6 | 0 如果我按数字升序排序,我得到: select * from test order by number asc; 6 | 0 5 | 1 4 | 2 3 | 3 2 | 4 1 | 5 如何对订单进行条带化以使其在每行的升序和降序之间交替? 6 | 0 or 1 | 5 1 | 5 6 | 0 5 | 1 2 | 4 2 | 4 5 | 1 4 | 2 3 | 3 3 | 3 4 | 2
更新
WITH x AS ( SELECT *,row_number() OVER (ORDER BY number) rn_up,row_number() OVER (ORDER BY number DESC) rn_down FROM test ) SELECT id,number FROM x ORDER BY LEAST(rn_up,rn_down),number; 要么: ... ORDER BY LEAST(rn_up,number DESC; 从更大的数字开始. 我一开始有两个CTE,但一个就够了 – 更简单,更快. (编辑:李大同) 【声明】本站内容均来自网络,其相关言论仅代表作者个人观点,不代表本站立场。若无意侵犯到您的权利,请及时与联系站长删除相关内容! |