Can't tell exactly without the DDL as mentioned by Sean.

But as you said you need get all results when a user inputs a date and neet to search with Year part. One option is to do like this.

declare @date datetime;--'11-2-2014'

SELECT Tagname,value

From runtime.dbo.History

WHERE Tagname IN ('Tag1', 'Tag2')

and wwVersion = 'Latest'

and

DATEPART(YY,datetime)= DATEPART(YY,@date)