mysql 查询不遵守日期参数

Question

我有一个问题如下:

SELECT   ch.id, ch.checkname, MAX(ch.CheckDate) AS CheckDate, 
         ch.SeverityNumber, md.CheckRef1, md.CheckSubject, 
         DATEDIFF(FROM_UNIXTIME( ch.CheckDate),CURDATE()) AS dateFromalarm 
FROM     checks ch, model md 
WHERE    ch.SysName='MV3R' 
AND      ch.environment='Z/OS' 
AND      md.CheckName=ch.CheckName 
AND      ***ch.CheckDate <=1569785343*** 
GROUP BY CheckName 
ORDER BY ch.CheckName DESC;

此查询应该为每个具有最新检查日期的检查名称返回一行。 checkname 不是唯一的，表中的每个 checkname 都有很多行。 问题是当我更改粗体部分中的数字时 (ch.CheckDate <=1569785343) 它根本不会改变结果.. 有什么想法吗？

Answer 1

让我们尝试隔离您的 max(checkdate) 以避免对多个列进行分组，我相信每个 checkname 您只有 1 个信息。

select ch.id
    , ch.checkname
    , t1.CheckDate
    , ch.SeverityNumber
    , md.CheckRef1
    , md.CheckSubject
    , datediff(from_unixtime(ch.CheckDate),CURDATE()) as dateFromalarm 
from 
    (select checkname, max(CheckDate)as CheckDate from checks where CheckDate <=1569785343 group by checkname) as t1
join checks ch on ch.checkname = t1.checkname
join model md on md.CheckName=ch.CheckName
where ch.SysName='MV3R' 
    and ch.environment='Z/OS'    
order by ch.CheckName desc;