initial commit

2026-05-12 16:40:03 +01:00
commit 647d1bfa7f
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+/*
+    Rolling period generator
+    ========================
+
+    Purpose:
+    Generate reusable rolling reporting windows for monthly outputs.
+
+    Use this first when a measure needs:
+    - one row per practice per period;
+    - a rolling lookback window;
+    - stable PeriodStartDate and PeriodEndDate columns for Excel or Power BI.
+*/
+
+SET FIRST_PERIOD_END_DATE = '2025-06-30';
+SET LAST_PERIOD_END_DATE = LAST_DAY(DATEADD('MONTH', -1, CURRENT_DATE()));
+SET LOOKBACK_MONTHS = 12;
+
+WITH RECURSIVE date_periods AS (
+    -- Month-end series; cap LAST_PERIOD_END_DATE before sharing a final report.
+    SELECT $FIRST_PERIOD_END_DATE::DATE AS "PeriodEndDate"
+    UNION ALL
+    SELECT LAST_DAY(DATEADD(MONTH, 1, "PeriodEndDate"))::DATE AS "PeriodEndDate"
+    FROM date_periods
+    WHERE "PeriodEndDate" < $LAST_PERIOD_END_DATE::DATE
+),
+rolling_periods AS (
+    -- Converts each period end into a fixed lookback window.
+    SELECT
+        DATEADD(MONTH, 1 - $LOOKBACK_MONTHS, DATE_TRUNC('MONTH', "PeriodEndDate"))::DATE AS "PeriodStartDate",
+        "PeriodEndDate",
+        $LOOKBACK_MONTHS AS "LookbackMonths"
+    FROM date_periods
+)
+SELECT
+    "PeriodStartDate",
+    "PeriodEndDate",
+    "LookbackMonths"
+FROM rolling_periods
+ORDER BY "PeriodEndDate";