PNLS taux de positivité

SELECT
    pcr1.id_patient,
    child.patient_code AS child_code,
    pcr1.date_of_birth,
    pcr1.date_blood_taken AS date_pcr1,
    result1.name AS pcr1_result,
    IF(pcr2.which_pcr = 2,
        pcr2.date_blood_taken,
        '') AS date_pcr2,
    result2.name AS pcr2_result,
    CONCAT(tm.mother_city_code,
            '/',
            tm.mother_hospital_code,
            '/',
            tm.mother_code) AS mother_code,
    IF(mother.id IS NOT NULL,
        'mother on hiv',
        'mother not on hiv') AS mother_status,
    is_PTME,
    PTME_date
FROM
    testing_specimen AS pcr1
        LEFT JOIN
    (SELECT
        *
    FROM
        testing_specimen
    WHERE
        which_pcr = 2) pcr2 ON pcr2.id_patient = pcr1.id_patient
        LEFT JOIN
    testing_mereenfant tm ON pcr1.id_patient = tm.id_patient
        LEFT JOIN
    patient mother ON mother.patient_code = CONCAT(tm.mother_city_code,
            '/',
            tm.mother_hospital_code,
            '/',
            tm.mother_code)
        LEFT JOIN
    tracking_motherbasicinfo ON tracking_motherbasicinfo.id_patient = mother.id
        LEFT JOIN
    lookup_testing_specimen_result AS result1 ON result1.id = pcr1.pcr_result
        LEFT JOIN
    lookup_testing_specimen_result AS result2 ON result2.id = pcr2.pcr_result
        LEFT JOIN
    patient AS child ON child.id = pcr1.id_patient
WHERE
    pcr1.which_pcr = 1
        AND pcr1.date_of_birth BETWEEN '2016-01-01' AND '2018-12-31'