我有一个查询,我需要每天运行不止一次。此查询正在将数据从一个数据库导入另一个。
目标表结构为:
Id Date Department Location PersonId Starttime EndTime State
1 2012-01-01 2 5 200 12:00:00.000 15:00:00.000 2
应用程序还可以将数据插入目标表。当该记录存在于具有另一种状态的源(临时表)表中时,应用程序插入的记录也可能不会更新。
为了使这成为可能,我创建了一个解决方案。我将在目标表中创建一个具有第二种状态的新列,以便我可以检查。
Id Date Department Location PersonId Starttime EndTime State StateSource
1 2012-01-01 2 5 200 12:00:00.000 15:00:00.000 2 2
一些要求:
如果应用程序添加了一条记录,则 StateSource 将为 NULL。意味着这条记录不能从源表中删除、更新或再次插入。
如果应用程序更新记录,则 State 和 StateSource 的值将不同。在这种情况下,我不更新此记录。
如果源表和目标表中的状态不同并且目标表中的值 State = StateSource,我将进行更新。
当目标表中不存在该记录时,我将插入一条记录。当记录已经存在时不要插入(无论这是由应用程序添加还是我在第一次运行时的查询)。
当我的源表和 State=StateSource 中不再存在记录时,我将从目标中删除记录。
我已经有以下查询。我决定发表3个声明。
--Delete Statement first
Delete from t
from TargetTable t LEFT JOIN SourceTable s ON t.Id=s.Id
and t.Date=s.Date
and t.departments=s.Department
and t.PersonId=s.PersonId
and t.State=t.StateSource
--Just delete if a date is no more exists from the source table and this records is NOT
--changed by the application (t.State=t.StateSource)
--Update statement second
Update t
set t.State = s.State
From Targettable t INNER JOIN SourceTable s ON t.Id=s.Id
and t.Date=s.Date
and t.departments=s.Department
and t.PersonId=s.PersonId
The problem here is:
--when I have State 2 already in the targettable and in my sourcetable i have
--another state then the state in the targettable changes. This would not be the case.
--Insert Statement thirth
insert into TargetTable (Id, Date, Department, Location, PersonId, Starttime, EndTime,State, StateSource)
select Id, Date, Department, Location, PersonId, Starttime, EndTime,State, StateSource
from SourceTable s
WHERE Date not in (select Date
from TargetTable t
where t.id=s.id
and t.PersonId=s.PersonId
and t.date=s.date
and t.department=s.department)
--I have no idea about how the insert should be because the application also can
--insert records. When a record exists then no insert. What to do with the State?
请记住,由应用程序更改的状态是领先的。
任何人都可以帮助我达到预期的结果吗?