How do I optimally read latest data from different tables in openmrs database

Question

I am trying to uniquely read latest patient data from openmrs database but it takes a lot of time and I want to know if their is a way I can optimize my SQL code to be efficient. below is the initial query

SELECT
    pid2.identifier AS HospitalNumber,
    pid1.identifier AS UniqueID,
    person.gender AS Gender,
    MAX(encounter.encounter_datetime) AS LatestVisitDate,
    CONCAT(pn.given_name, ' ', pn.family_name) AS Patient_Name,
    CAST(psn_atr.value AS CHAR) AS Phone_No,
    pa.address1 AS Patient_Address,
    pa.city_village AS Patient_LGA,
    pa.state_province AS Patient_State,
    MAX(IF(obs.concept_id = 159599, obs.value_datetime, NULL)) AS ART_Start_Date
--    MAX(IF((obs.concept_id=165708 and encounter.form_id=27 AND obs.obs_datetime <= @endDate AND obs.voided =0),container.last_date,null)) as Pharmacy_LastPickupdate
FROM patient_identifier AS pid2
JOIN patient_identifier AS pid1 ON pid2.patient_id = pid1.patient_id
INNER JOIN encounter ON encounter.patient_id = pid2.patient_id
INNER JOIN person ON person.person_id = pid2.patient_id
INNER JOIN person_name AS pn ON pn.person_id = pid2.patient_id
LEFT JOIN person_attribute AS psn_atr ON psn_atr.person_id = pid2.patient_id
    AND psn_atr.person_attribute_type_id = (SELECT person_attribute_type_id FROM person_attribute_type WHERE name = 'Telephone Number')
LEFT JOIN person_address AS pa ON pa.person_id = pid2.patient_id
LEFT JOIN obs ON obs.person_id = pid2.patient_id
WHERE pid2.identifier_type = 5 AND pid1.identifier_type = 4
AND encounter.voided = 0 AND pid1.voided = 0
GROUP BY pid2.identifier, pid1.identifier, person.gender, person.birthdate, Patient_Name, Phone_No, Patient_Address, Patient_LGA, Patient_State;

I have tried using a subquery for my query but I discovered that more rows were added which is not what I want below is the query I tried

SELECT
    pid2.identifier AS HospitalNumber,
    pid1.identifier AS UniqueID,
    person.gender AS Gender,
    encounter.encounter_datetime AS LatestVisitDate,
    CONCAT(pn.given_name, ' ', pn.family_name) AS Patient_Name,
    CAST(psn_atr.value AS CHAR) AS Phone_No,
    pa.address1 AS Patient_Address,
    pa.city_village AS Patient_LGA,
    pa.state_province AS Patient_State,
    obs_art_start_date.max_art_start_date AS ART_Start_Date
FROM patient_identifier AS pid2
JOIN patient_identifier AS pid1 ON pid2.patient_id = pid1.patient_id
INNER JOIN encounter ON encounter.patient_id = pid2.patient_id
INNER JOIN person ON person.person_id = pid2.patient_id
INNER JOIN person_name AS pn ON pn.person_id = pid2.patient_id
LEFT JOIN person_attribute AS psn_atr ON psn_atr.person_id = pid2.patient_id
    AND psn_atr.person_attribute_type_id = (SELECT pa_type.person_attribute_type_id FROM person_attribute_type AS pa_type WHERE pa_type.name = 'Telephone Number')
LEFT JOIN person_address AS pa ON pa.person_id = pid2.patient_id
LEFT JOIN (
    SELECT
        obs.person_id,
        MAX(obs.value_datetime) AS max_art_start_date
    FROM obs
    WHERE obs.concept_id = 159599
    GROUP BY obs.person_id
) AS obs_art_start_date ON obs_art_start_date.person_id = pid2.patient_id
WHERE pid2.identifier_type = 5 AND pid1.identifier_type = 4
    AND encounter.voided = 0 AND pid1.voided = 0;