Hmmm,
How about:

DECLARE @Temp TABLE (table1ID int, Table2Id, StartDate Datetime, EndDate DateTime)
INSERT INTO @Temp 
SELECT Table1.Id,
       Table2.Id,
       Table2.StartDate,
       Table2.EndDate
FROM Table1
FULL JOIN Table2 ON 1=1


SELECT .....
    FROM Table1
    LEFT JOIN @Temp Temp ON Table1.Id = Temp.Id AND Table1.EffectiveDate BETWEEN Temp.StartDate AND Temp.EndDate

I am not sure if this would speed something.


>Table1 contains a record for each day that contains certain interest rates.
>Table2 contains a record for a range of days (specified by StartDate and EndDate - no overlap) that contains other interest rates.
>
>I want to link the tables, and view the corresponding Table2 record with each Table1 record. The tables are unrelated otherwise.