目前我在查询中显示最高值:
ORDER BY Height DESC
) T
WHERE RowNum = 1
显示最高值,例如10,但如果两个条目的值相同,则会怎样10。
如何制作它以显示两个联合最高值?
答案 0 :(得分:2)
在Oracle中使用,使用秩分析
select a, b
from (select a, b, rank() over (order by height desc) rnk
from your_table)
where rnk = 1;
答案 1 :(得分:1)
一种解决方案是使用CTE
使用CTE
;WITH q AS (
SELECT MAX(Height) AS maxHeight
FROM YourTable
)
SELECT *
FROM YourTable
INNER JOIN q ON q.maxHeight = Yourtable.Height
或带有子选择的普通where子句
SELECT *
FROM YourTable
WHERE Height = (SELECT MAX(Height) FROM YourTable)
就个人而言,我更喜欢使用CTE,因为它不会使语句混乱(好吧,在这个简单的情况下不是这样,但在实践中,我经常发现它比子选择更具可读性)。
答案 2 :(得分:0)
这样做也很简单,
Select height from table where height=(select max(height) from table)
答案 3 :(得分:0)
这里你没有子查询,它更复杂但创建起来很有趣。
select ifnull(@d,@d:=actor_id),actor_id,if(@d>actor_id,1,0)as t
from t1 having t=0 order by actor_id desc;
这是我计算机中的示例。
mysql> desc t1;
+-------------+----------------------+------+-----+---------------------+-------+
| Field | Type | Null | Key | Default | Extra |
+-------------+----------------------+------+-----+---------------------+-------+
| actor_id | smallint(5) unsigned | NO | | 0 | |
| first_name | varchar(45) | NO | | NULL | |
| last_name | varchar(45) | NO | | NULL | |
| last_update | timestamp | NO | | 0000-00-00 00:00:00 | |
+-------------+----------------------+------+-----+---------------------+-------+
4 rows in set (0.00 sec)
mysql> select * From t1 order by actor_id desc limit 5;
+----------+------------+-----------+---------------------+
| actor_id | first_name | last_name | last_update |
+----------+------------+-----------+---------------------+
| 20001 | test | test | 2012-12-13 09:12:50 |
| 20001 | test | test | 2012-12-13 09:12:51 |
| 2000 | b | a | 0000-00-00 00:00:00 |
| 2000 | b | a | 0000-00-00 00:00:00 |
| 2000 | b | a | 0000-00-00 00:00:00 |
+----------+------------+-----------+---------------------+
5 rows in set (0.00 sec)
mysql> select ifnull(@d,@d:=actor_id),actor_id,if(@d>actor_id,1,0)as t
-> from t1 having t=0 order by actor_id desc;
+-------------------------+----------+---+
| ifnull(@d,@d:=actor_id) | actor_id | t |
+-------------------------+----------+---+
| 20001 | 20001 | 0 |
| 20001 | 20001 | 0 |
+-------------------------+----------+---+
2 rows in set (0.00 sec)