为什么这个SQL语句不检索DISTINCT记录

Question

我有2个表，Jobs和AdminUsersLog。 AdminUsersLog包含作业中每个作业记录上执行的操作日志。

我正在尝试检索空闲时间超过7天的作业列表。下面的这个SQL似乎是拉出每个作业的所有日志条目，因此从日志中提取较早的条目，当然这些条目总是会超过7天。

我需要为AdminUsersLog.ulDate早于7天的每个作业检索一条记录。

SELECT DISTINCT Jobs.ID, Jobs.bStatus AS jStatus, Jobs.sID, Jobs.insDate, Jobs.statusLabel, Jobs.cID, AdminUsersLog.ulDate, AdminUsersLog.ulJobType 
FROM AdminUsersLog LEFT JOIN Jobs 
ON (AdminUsersLog.ulJobID = Jobs.ID AND AdminUsersLog.ulJobType = 1) 
WHERE AdminUsersLog.ulJobType = 1 
AND (SELECT TOP(1) AdminUsersLog.ulDate FROM AdminUsersLog WHERE AdminUsersLog.ulJobID =  Jobs.ID AND AdminUsersLog.ulJobType = 1) < DATEADD(dd,-7,GETDATE()) 
AND Jobs.bStatus < 8 

Top X results; http://pastebin.com/RcvxbxCV

Answer 1

您设定ulDate列

AS

SELECT CONVERT(DATE,ulDate) AS ulDate 

ON选择字段

SELECT CAST('2014-01-23 15:23:42.093' AS DATE) like this 

beause您ulDate场不明显

查询设置为

SELECT  DISTINCT Jobs.ID, Jobs.bStatus AS jStatus, Jobs.sID, Jobs.insDate, Jobs.statusLabel, Jobs.cID, 
       CONVERT(DATE,AdminUsersLog.ulDate) AS ulDate, AdminUsersLog.ulJobType 
    FROM  AdminUsersLog 
    LEFT JOIN Jobs ON (AdminUsersLog.ulJobID = Jobs.ID AND AdminUsersLog.ulJobType = 1) 
    WHERE  AdminUsersLog.ulJobType = 1 
       AND (SELECT TOP(1) AdminUsersLog.ulDate FROM AdminUsersLog WHERE AdminUsersLog.ulJobID = Jobs.ID AND AdminUsersLog.ulJobType = 1) < DATEADD(dd,-7,GETDATE()) 
       AND Jobs.bStatus < 8 

Answer 2

看

这将让你在工作中的条目。这可以是任何匹配的条目，因为您没有为TOP表达式指定排序顺序。大多数情况下，随机挑选的条目将会老化。因此，要么指定排序顺序：

SELECT TOP(1) AdminUsersLog.ulDate 
FROM AdminUsersLog 
WHERE AdminUsersLog.ulJobID = Jobs.ID AND AdminUsersLog.ulJobType = 1 
ORDER BY ulDate DESC 

或者干脆使用MAX：

SELECT MAX(AdminUsersLog.ulDate) 
FROM AdminUsersLog 
WHERE AdminUsersLog.ulJobID = Jobs.ID AND AdminUsersLog.ulJobType = 1