例如,该表具有列 MYINDEX 和 NAME。
MYINDEX | NAME
=================
1 | BOB
2 | BOB
3 | CHARLES
我如何找到特定名称的 MYINDEX 最高的行?例如,我想查找名称“BOB”的 ROW-2。
SELECT Max(MYINDEX) FROM table WHERE NAME = [insertNameHere]
编辑:获取整行:
Select * //never do this really
From Table
Where MYINDEX = (Select Max(MYINDEX) From Table Where Name = [InsertNameHere]
SELECT MAX(MYINDEX) FROM table
WHERE NAME = 'BOB'
对于整行,请执行以下操作:
SELECT * FROM table
WHERE NAME = 'BOB'
AND MyIndex = (SELECT Max(MYINDEX) from table WHERE NAME = 'BOB')
有几种方法可以解决这个问题。我假设您可能希望从该行中获得其他列,否则正如其他人所说,只需命名即可MAX(my_index) ... GROUP BY name
。这里有几个例子:
SELECT
MT.name,
MT.my_index
FROM
(
SELECT
name,
MAX(my_index) AS max_my_index
FROM
My_Table
GROUP BY
name
) SQ
INNER JOIN My_Table MT ON
MT.name = SQ.name AND
MT.my_index = SQ.max_my_index
另一种可能的解决方案:
SELECT
MT1.name,
MT1.my_index
FROM
My_Table MT1
WHERE
NOT EXISTS
(
SELECT *
FROM
My_Table MT2
WHERE
MT2.name = MT1.name AND
MT2.my_index > MT1.my_index
)
如果您想查看 name = 'Bob' 的最高索引,请使用:
SELECT MAX(MYINDEX) AS [MaxIndex]
FROM myTable
WHERE Name = 'Bob'
如果你想跳过内部连接,你可以这样做:
SELECT * FROM table WHERE NAME = 'BOB' ORDER BY MYINDEX DESC LIMIT 1;
利用
FROM TABLE SELECT MAX(MYINDEX), NAME GROUP BY NAME