Question

PostgreSQL支持此查询，但是由于Over（partition by），H2无法运行查询。问题是如何只选择两行中具有不同值的最新创建时间的一行。

Example:
id  name  created     ecid  psid
 1    aa  2019-02-07     1     1
 2    bb  2019-02-01     1     1
 3    cc  2019-02-05     2     2
 4    dd  2019-02-06     2     3
 5    ee  2019-02-08     2     3

Result:
id  name  created     ecid  psid
 1    aa  2019-02-07     1     1
 3    cc  2019-02-05     2     2
 5    ee  2019-02-08     2     3  




SELECT s.*, MAX(s.created) OVER (PARTITION BY s.ecid, s.psid) AS latest FROM ...
WHERE latest = created

Answer 1

使用相关子查询

select t1.* from table t1
where t1.created = ( select max(created) 
from table t2 where t1.ecid=t2.ecid and t1.psid=t2.psid)

Answer 2

使用NOT EXISTS：

select t.* from tablename t
where not exists (
  select 1 from tablename
  where ecid = t.ecid and psid = t.psid and created > t.created
)

通过更多条件仅选择一行

2 个答案: