Question

我在数据库中有以下数据，主键是字段SEQ，我希望选择具有最大seq的数据：

ID     SEQ   FILE
1007   1     abc
1007   2     def

以下查询无效，但我希望做同样的事情。

SELECT * FROM table1 WHERE id = '1007' AND Max(seq)

Answer 1

SELECT id, seq, file
FROM ( 
   select id, seq, file, 
          max(seq) over (partition by id) as max_seq
   from table1 
   WHERE id = '1007'
) t 
where seq = max_seq;

Answer 2

如果我理解正确，你希望这样的事情

select * 
from (select t.*, 
      max(t.seq) 
        keep (dense_rank first order by t.seq desc) 
        over (partition by t.id) max#
from table1 t) 
where seq = max#

Answer 3

另一种方法：

select id,seq,"FILE" from 
(select t1.*,row_number() over (partition by id order by seq desc) cont_seq 
from your_table t1)
where cont_seq = 1
order by seq;

这将为您提供按ID分组且具有最大seq值的所有行。如果你想要一个特定的值，只需在where子句中添加条件，如下所示：

select id,seq,"FILE" from 
(select t1.*,row_number() over (partition by id order by seq desc) cont_seq 
from your_table t1)
where cont_seq = 1 and id = '1007'
order by seq;

Answer 4

select * from alber.table1;

MYID SEQ FILENAME

1007 2 abc
1007 10 def
1008 45 abc
1008 9 def

SELECT myid, seq, filename from alber.table1 mq where seq = (select max(seq) from alber.table1 sq where sq.myid = mq.myid);

MYID SEQ FILENAME

1007 10 def
1008 45 abc

获取最大数量的Oracle SQL

4 个答案: