DELETE 
FROM
	EMP 
WHERE
	NOT EXISTS ( 
		SELECT
			  1 
		FROM
			EMP_INVALID 
		WHERE
			EMP.EMP_CODE = EMP_INVALID.EMP_CODE 
			AND EMP.VALID_FLG <> EMP_INVALID.VALID_FLG
	) 
	AND emp.VALID_FLG = '0'
;