comparing dates giving unexpected error

[alh1002]

So I have a table where ladder_date is stored as Date/Time

I then have the following query
Select B.book_name,B.ladder_date,B.BOM,B.NAV,B.gMTDRT,B.gMTDPER,B.PreviousDay,Base, B.gTDRT,B.gTDCHANGEPER, (select ((Exp(SUM(Log(1+A.gTDCHANGEPER/100)))-1)*100) AS YTD

from Daily_tt A
where B.ladder_date < A.ladder_date)
from Daily_tt B;


and it is returning an error, "Data type mismatch in criteria expression"

but if I use an "=" it works, but I want the less than sign.

Any thoughts on why this is happening?

 

[Golom]

Select B.book_name,B.ladder_date,B.BOM,B.NAV,B.gMTDRT,B.gMTDPER,B.PreviousDay,Base, B.gTDRT,B.gTDCHANGEPER, 

(select Exp(SUM(Log(1+A.gTDCHANGEPER/100)))-1)*100 
 from Daily_tt A
 where B.ladder_date < A.ladder_date
   [COLOR=red]AND A.gTDCHANGEPER IS NOT NULL) AS YTD
[/color]

from Daily_tt B;

or

Select B.book_name,B.ladder_date,B.BOM,B.NAV,B.gMTDRT,B.gMTDPER,B.PreviousDay,Base, B.gTDRT,B.gTDCHANGEPER, 

Exp(SUM(Log(1+A.gTDCHANGEPER/100)))-1)*100  AS YTD

FROM Daily_tt B INNER JOIN Daily_tt A
     ON A.ladder_date > B.ladder_date

Where A.gTDCHANGEPER IS NOT NULL

Group By B.book_name,B.ladder_date,B.BOM,B.NAV,B.gMTDRT,B.gMTDPER,
B.PreviousDay,Base, B.gTDRT, B.gTDCHANGEPER

Which makes sense only of Ladder_Date is a unique key.

[small]No! No! You're not thinking ... you're only being logical.
- Neils Bohr[/small]