how do I subtract values from two select statements
- by fishhead
I would like to subtract one value from another value. The schema of the table is as follows:
tag, datetime,value
------------
tag1, 2010-1-1 10:10:00, 123
tag2, 2010-2-2 10:12:00. 321
select * from
( (Select Max(Value) as [Value1] from History WHERE Datetime ='2010-1-1 10:10' and tagname ='tag1') as v1 -
( (Select Max(Value) as [Value2] from History WHERE Datetime ='2010-1-1 10:12' and Tagname ='tag2') as v2))
obviously I am lost...how do I do this.
thanks
ms-sql