example code :

select top 1 name from DIRPARTYTABLE
inner join HcmWorker ON HcmWorker.PERSON = DIRPARTYTABLE.RECID
AND HcmWorker.RECID = 
	(select top 1 worker from HCMPOSITIONWORKERASSIGNMENT  
	INNER JOIN HCMPOSITION ON HCMPOSITIONWORKERASSIGNMENT.POSITION =  HCMPOSITION.RECID
	AND HCMPOSITION.POSITIONID = 'P0003' 
	where GETDATE() between HCMPOSITIONWORKERASSIGNMENT.VALIDFROM AND HCMPOSITIONWORKERASSIGNMENT.VALIDTO);