-- Snowflake version: Check prescribing by VTM (Virtual Therapeutic Moiety)
-- Uses unified PrimaryCareMedication table (combines EMIS + TPP)

SET StartDate = '2025-05-01';
SET EndDate = '2025-11-30';

WITH SnomedCodes AS (
    SELECT "ProductSnomedCode", "ProductDescription"
    FROM DATA_HUB.DWH."DimMedicineAndDevice"
    WHERE "TherapeuticMoietySnomedCode" = '41145911000001106'  -- Tirzepatide VTM
)
SELECT
    DATE_TRUNC('MONTH', pcm."DateMedicationStart") AS PrescribingMonth,
    COUNT(DISTINCT dp."PersonKey") AS UniquePatientCount
FROM DATA_HUB.PHM."PrimaryCareMedication" pcm
INNER JOIN DATA_HUB.DWH."DimPerson" dp
    ON pcm."PatientPseudonym" = dp."PatientPseudonym"
INNER JOIN SnomedCodes sc
    ON pcm."SNOMEDCode" = sc."ProductSnomedCode"
INNER JOIN DATA_HUB.DWH."DimOrganisationAndSite" dos
    ON dp."CurrentGeneralPractice" = dos."SiteCode"
WHERE pcm."DateMedicationStart" BETWEEN $StartDate AND $EndDate
    AND pcm."PatientPseudonym" IS NOT NULL
    AND dos."OrganisationSubType" = 'GP Practice'
    AND dos."IsSiteNorfolkAndWaveney" = 'Yes'
    AND dos."IsSiteActive" = 'Yes'
GROUP BY DATE_TRUNC('MONTH', pcm."DateMedicationStart")
ORDER BY PrescribingMonth