/*
    Latest data dates
    =================

    Purpose:
    Check freshness anchors before deciding reporting periods.

    Notes:
    - Dispensing uses ProcessingPeriodDate and usually lags.
    - Unified prescribing DateMedicationStart can include future starts, so the
      TPP DateEventRecorded probe is included as a more conservative source
      event freshness marker.
*/

SELECT
    'NATIONAL.GPMED.MedicinesDispensedInPrimarycare' AS "Source",
    MAX("ProcessingPeriodDate")::DATE AS "LatestDate"
FROM NATIONAL.GPMED."MedicinesDispensedInPrimarycare"

UNION ALL

SELECT
    'REPORTING_DATASETS_ICB.SCRATCHPAD.MEDS__UnifiedPrescribingTable DateMedicationStart' AS "Source",
    MAX("DateMedicationStart")::DATE AS "LatestDate"
FROM REPORTING_DATASETS_ICB.SCRATCHPAD."MEDS__UnifiedPrescribingTable"
WHERE "DateMedicationStart" <= CURRENT_DATE()

UNION ALL

SELECT
    'PRIMARY_CARE.TPP.SRPrimaryCareMedication DateEventRecorded' AS "Source",
    MAX(CAST("DateEventRecorded" AS DATE)) AS "LatestDate"
FROM PRIMARY_CARE.TPP."SRPrimaryCareMedication"
WHERE "DateEventRecorded" >= DATEADD('MONTH', -3, CURRENT_DATE())
ORDER BY "Source";