我知道这是Select Rows with Maximum Column Value group by Another Column的副本,但我想选择具有最大列值的行,作为另一列的分组,但没有嵌套的select语句,我知道可以这样做:
SELECT
T.Name,
T.Rank,
T.ID
FROM MyTable T
WHERE T.Rank = (
SELECT MAX( T1.Rank) FROM MyTable T1
WHERE T1.Name= T.Name
)
其中ID,
Rank,
Name
是表架构,我想先按名称按结果分组,然后从每个名称组中选择一行,具体取决于哪一行具有最高等级。
附件是我想要选择的表格的示例
答案 0 :(得分:2)
mysql> SELECT t1.nm, t1.rank,t1.id
FROM mytable t1
LEFT JOIN (
SELECT nm, max(rank) as top
FROM mytable t2
GROUP BY nm
) AS t2 ON t1.nm=t2.nm AND t1.rank = t2.top
WHERE t2.nm IS not NULL
ORDER BY nm;
+----+------+---------+
| nm | rank | id |
+----+------+---------+
| m | -1 | b7kjhsf |
| n | 13 | d3sf |
+----+------+---------+
2 rows in set (0.00 sec)
mysql> select * from mytable;
+----+------+----------+
| nm | rank | id |
+----+------+----------+
| n | 11 | asfd |
| n | 11 | bsf |
| n | 11 | zzasdfsf |
| n | 13 | d3sf |
| n | 11 | effesf |
| n | 10 | yxxgesf |
| n | 11 | bkhjusf |
| m | -1 | b7kjhsf |
| m | -4 | cdfgabsf |
+----+------+----------+
9 rows in set (0.00 sec)
答案 1 :(得分:0)
正如在另一个答案中所提到的,我所知道的唯一其他选择是使用公用表表达式:
;WITH CTE AS
(
T.Name,
T.Rank,
T.ID,
ROW_NUMBER() OVER
(PARTITION BY Name ORDER BY Rank DESC)
AS RowNumber
FROM MyTable
)
SELECT *
FROM CTE
WHERE RowNumber = 1
答案 2 :(得分:0)
SELECT Name, Id, Rank FROM
(
SELECT T.Name, T.Id, T.Rank, RANK() OVER (PARTITION BY T.Name ORDER BY T.Rank DESC) = 1 AS NameRank
FROM MyTable T
)
WHERE NameRank = 1
答案 3 :(得分:0)
不确定您是否只是尝试排除嵌套选择,以及是否可以接受加入aginst的子选择。如果是这样的话: -
SELECT
T.Name,
T.Rank,
T.ID
FROM MyTable T
INNER JOIN (SELECT Name, MAX(Rank) AS MaxRank FROM MyTable GROUP BY Name ) T1
ON T.Name = T1.Name
AND T.Rank = T1.MaxRank