mysql - 从查询中返回最大值

Question

我正在尝试创建一个查询以返回具有最大版本的文件，与服务器的值无关。我怎么能那样做？

实际表格数据:

server    filename    v4    date
local     code1.zip   41    0000-00-00
remote    code1.zip   39    0000-00-00
local     code1.zip   28    0000-00-00
remote    code1.zip   21    0000-00-00
local     code1.zip   32    0000-00-00
remote    code1.zip   27    0000-00-00

查询:

SELECT
    server,
    filename,
    max(v4) as v4,
    date
FROM
    table
WHERE
    date ='0000-00-00'

GROUP BY
    filename,
    server,
    date

实际结果:

server    filename    v4    date
local     code1.zip   41    0000-00-00
remote    code1.zip   39    0000-00-00

预期结果:

server    filename    v4    date
local     code1.zip   41    0000-00-00

编辑:适用于 MySQL

提前致谢。

Answer 1

如果您只想要具有最大 v4 的行，您可以使用它

SELECT
    server,
    filename,
    v4,
    date
FROM
    `table`
WHERE
    date ='0000-00-00'
ORDER BY v4 DESC
LIMIT 1

要获得每个文件名的最大 V4，首先你要按文件名获得 max(v4) 组，然后使用 table INNER JOIN 返回，如下所示

SELECT T1.server,T1.filename,T1.v4,T1.date
FROM
`table` T1 INNER JOIN
    (SELECT filename,max(v4) as maxv4
     FROM `table`
     WHERE date = '0000-00-00'
     GROUP BY filename)T2
ON T1.filename = T2.filename AND T1.v4 = T2.maxV4
WHERE date = '0000-00-00';