My solution would be to write the sql code in a procedure and generate it dynamically. For example:

create proc MyProc

@Conditional varchar(10) = (For example) '<='

,@DateVal dateTime = (For example) '20130301'

as

BEGIN

declare @sql varchar(max)

set @sql = "Select etc etc where DateField " + @Conditional + " " + @DateVal + "etc etc"

exec @sql

END