What you're tring to acomplish? I'm not sure what is your definiton of 'steps' for a query and why it's so importent that there was only one step in a query. Anyway, following query uses correlated subquery.

SELECT * FROM t1 ;
	WHERE EffectiveDate IN ( ;
		SELECT max(EffectiveDate) ;
  from t1 t1_2 ;
  where EffectiveDate <= ?dParam ;
  	AND t1_2.Empid = t1.empid ) 

>Hi Sergey,
>This is still 2 steps, just combined onto 1 line of code.
>I was really hoping for something that would only "use t1 shared" once during the process.
>This is probably the best that can be done, but I'm still hoping.
>
>
>>This query should work

SELECT * FROM t1 ;
>>	WHERE STR(EmpId) + Dtos(EffectiveDate) IN ( ;
>>		Select Str(EmpID) + Dtos(max(EffectiveDate)) ;
>>  from t1 ;
>>  where EffectiveDate <= ?dParam ;
>>  group by EmpID )
>>

>>