data/sql/160_refresh_ekb_districts_median_dedup.sql

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+-- Fix: dedup deals-to-district assignment in ekb_districts median refresh.
+--
+-- Context: 67_refresh_ekb_districts_median.sql introduced ST_Intersects(district.geom, quarter.geom)
+-- to join cadastral quarters to districts. A quarter whose polygon straddles a district boundary
+-- matched BOTH districts, causing its deals to be counted in multiple districts and skewing
+-- the PERCENTILE_CONT / AVG aggregates.
+--
+-- Fix approach: replace ST_Intersects with ST_Within(ST_Centroid(cq.geom), d.geom).
+-- The centroid of each cadastral quarter falls in exactly one district polygon, guaranteeing
+-- a 1:1 quarter→district assignment. A DISTINCT ON fallback (ordered by d.district_name) is
+-- added in case district polygons overlap at all (they should not, but defensive).
+--
+-- Measured impact (prod, 2026-06-17, 24-month window):
+--   ST_Intersects  → 2945 deal-rows (2482 quarter-district pairs, 85 duplicate quarter pairs)
+--   ST_Within(centroid) → 2638 deal-rows (2396 quarter-district pairs, 0 duplicates)
+--   Eliminated: 307 spurious deal-district assignments.
+--
+-- Dependencies: ekb_districts_geom (geom), cad_quarters_geom (geom, cad_number),
+--               rosreestr_deals (quarter_cad_number, region_code, doc_type,
+--               realestate_type_code, area, price_per_sqm, period_start_date),
+--               ekb_districts (district_name, median_price_per_m2, mean_price_per_m2).
+--
+-- 67_refresh_ekb_districts_median.sql ran on prod; this file supersedes it via _schema_migrations.
+-- No dependent views or FK constraints on the function itself.
+-- Signature unchanged — all existing callers (analytics_refresh.py, beat_schedule.py, etc.)
+-- continue to work without modification.
+--
+-- Deploy order: this file only (no backend code change required).
+-- Idempotent: CREATE OR REPLACE FUNCTION — safe to re-run.
+
+BEGIN;
+
+CREATE OR REPLACE FUNCTION refresh_ekb_districts_median(window_months int DEFAULT 24, min_deals int DEFAULT 50)
+RETURNS TABLE(district_name text, deals_used bigint, median_pm numeric, mean_pm numeric)
+LANGUAGE plpgsql AS $$
+BEGIN
+    RETURN QUERY
+    WITH
+    -- Assign each cadastral quarter to exactly ONE district via centroid containment.
+    -- ST_Within(centroid, district_geom) is 1:1 whereas ST_Intersects matched border-
+    -- straddling quarters to multiple districts, inflating counts and skewing medians.
+    -- DISTINCT ON (cq.cad_number) with deterministic ORDER BY guards against the edge
+    -- case of overlapping district polygons.
+    quarter_district AS (
+        SELECT DISTINCT ON (cq.cad_number)
+               cq.cad_number,
+               d.district_name
+          FROM cad_quarters_geom cq
+          JOIN ekb_districts_geom d
+            ON ST_Within(ST_Centroid(cq.geom), d.geom)
+         WHERE d.district_name <> 'не определён'
+         ORDER BY cq.cad_number, d.district_name
+    ),
+    per_district AS (
+        SELECT qd.district_name,
+               COUNT(*)::bigint AS deals,
+               PERCENTILE_CONT(0.5) WITHIN GROUP (ORDER BY rd.price_per_sqm)::numeric AS p_median,
+               AVG(rd.price_per_sqm)::numeric AS p_mean
+          FROM rosreestr_deals rd
+          JOIN quarter_district qd ON qd.cad_number = rd.quarter_cad_number
+         WHERE rd.region_code = 66
+           AND rd.doc_type = 'ДДУ'
+           AND rd.realestate_type_code = '002001003000'
+           AND rd.area BETWEEN 15 AND 200
+           AND rd.price_per_sqm BETWEEN 30000 AND 1000000
+           AND rd.period_start_date >= NOW() - (window_months || ' months')::interval
+         GROUP BY qd.district_name
+    ),
+    upd AS (
+        UPDATE ekb_districts e
+           SET median_price_per_m2 = ROUND(pd.p_median, 0),
+               mean_price_per_m2   = ROUND(pd.p_mean, 0)
+          FROM per_district pd
+         WHERE e.district_name = pd.district_name
+           AND e.district_name <> 'не определён'
+           AND pd.deals >= min_deals
+        RETURNING e.district_name, pd.deals, pd.p_median, pd.p_mean
+    )
+    SELECT u.district_name::text, u.deals, ROUND(u.p_median, 0), ROUND(u.p_mean, 0)
+      FROM upd u
+     ORDER BY u.district_name;
+END;
+$$;
+
+COMMENT ON FUNCTION refresh_ekb_districts_median(int, int) IS
+    'Refresh ekb_districts.median_price_per_m2 + mean_price_per_m2 из ДДУ-сделок rosreestr_deals. '
+    'Spatial join: ST_Within(ST_Centroid(cad_quarter), district) — каждый квартал ровно в одном районе '
+    '(fixes ST_Intersects double-count на граничных кварталах; issue #1352). '
+    'Окно по умолчанию 24 мес, минимум 50 сделок на район. Запускается Celery beat раз в месяц.';
+
+COMMIT;