I can definitely try that but what does 

CASE WHEN NVL(quantity,'')='' OR NVL(quantity_unit,'')='' THEN ''
                       ELSE quantity || ' ' || quantity_unit || ' '
                  END || frequency_description
END || mean?

What does those symbols represent, I am new to cache so trying to learn. Thank You

full code

SELECT (CASE WHEN (order_description IS NULL OR (order_description='')) THEN ''
ELSE (order_description) END) !!
(CASE WHEN (dosage IS NULL OR dosage_unit IS NULL OR (dosage='') OR (dosage_unit='')) THEN ''
ELSE (', ' !! dosage !! ' ' !! dosage_unit !!
(CASE WHEN (dosage_form IS NULL OR (dosage_form='')) THEN ''
ELSE (' ' !! dosage_form) END) !! '') END) !!
(CASE WHEN (administration_route IS NULL OR (administration_route='')) THEN ''
ELSE (', ' !! administration_route) END) !!
(CASE WHEN (frequency_description IS NULL OR (frequency_description='')) THEN ''
ELSE (', ' !! (CASE WHEN (quantity IS NULL OR quantity_unit IS NULL OR
(quantity='') OR (quantity_unit='')) THEN ''
ELSE (quantity !! ' ' !! quantity_unit !! ' ') END) !! frequency_description) END) !!
(CASE WHEN start_date IS NULL THEN '' ELSE (', ' !! 'Start Date: ' !!
CONVERT(SQL_DATE,start_date,101)) END) As MedicationOrder
FROM CWSOrderEntry.history_client_order
WHERE PATID='100068'
--AND FACILITY=?FACILITY
AND order_status_code='A'
AND order_type_category_code='P'

full code

SELECT (CASE WHEN (order_description IS NULL OR (order_description='')) THEN ''
ELSE (order_description) END) !!
(CASE WHEN (dosage IS NULL OR dosage_unit IS NULL OR (dosage='') OR (dosage_unit='')) THEN ''
ELSE (', ' !! dosage !! ' ' !! dosage_unit !!
(CASE WHEN (dosage_form IS NULL OR (dosage_form='')) THEN ''
ELSE (' ' !! dosage_form) END) !! '') END) !!
(CASE WHEN (administration_route IS NULL OR (administration_route='')) THEN ''
ELSE (', ' !! administration_route) END) !!
(CASE WHEN (frequency_description IS NULL OR (frequency_description='')) THEN ''
ELSE (', ' !! (CASE WHEN (quantity IS NULL OR quantity_unit IS NULL OR
(quantity='') OR (quantity_unit='')) THEN ''
ELSE (quantity !! ' ' !! quantity_unit !! ' ') END) !! frequency_description) END) !!
(CASE WHEN start_date IS NULL THEN '' ELSE (', ' !! 'Start Date: ' !!
CONVERT(SQL_DATE,start_date,101)) END) As MedicationOrder
FROM CWSOrderEntry.history_client_order
WHERE PATID='100068'
--AND FACILITY=?FACILITY
AND order_status_code='A'
AND order_type_category_code='P'