76 lines
3.4 KiB
PL/PgSQL
76 lines
3.4 KiB
PL/PgSQL
-- 120_backfill_kn_price_per_m2.sql
|
|
-- Context: Issue #573 — domrf_kn_flats.price_per_m2 is populated in only ~3.7%
|
|
-- of rows (status='free'/'sold'/'booked'). The 756 977 NULL-status rows imported
|
|
-- from historical DOM.RF snapshots carry total_area but no price_rub, so the
|
|
-- scraper's price_rub/total_area derivation never fires for them.
|
|
-- This leaves 5/8 EKB districts with 0% price_per_m2 coverage and NULL district
|
|
-- medians, blocking the Limit_District_Median_Partial analytics limitation.
|
|
--
|
|
-- Strategy (three-pass, most-precise source first):
|
|
-- Pass 1 — direct arithmetic: price_rub / total_area where both columns present
|
|
-- and price_per_m2 is still NULL or zero. Covers any rows the scraper
|
|
-- missed (idempotent sanity net).
|
|
-- Pass 2 — sale_graph join: use domrf_kn_sale_graph.price_avg (type='apartments',
|
|
-- latest snapshot) as a proxy for the object-level avg ₽/м². Applied
|
|
-- only to rows where Pass 1 left price_per_m2 NULL and the object has
|
|
-- a sale_graph row.
|
|
-- Pass 3 — peer median: for objects without sale_graph, derive price_per_m2 from
|
|
-- the PERCENTILE_CONT(0.5) of free/sold/booked flats in the same obj_id.
|
|
--
|
|
-- Idempotent: WHERE price_per_m2 IS NULL guard prevents re-overwriting correct values.
|
|
-- Dependencies: domrf_kn_flats, domrf_kn_sale_graph (migration 50_schema_kn_extensions.sql).
|
|
-- Apply order: after 99_nspd_entities_denorm.sql.
|
|
-- Estimated runtime on prod: < 30 s (785 K rows, index on obj_id exists).
|
|
|
|
BEGIN;
|
|
|
|
-- ── Pass 1: direct price_rub / total_area ────────────────────────────────────
|
|
UPDATE public.domrf_kn_flats
|
|
SET price_per_m2 = ROUND(price_rub / total_area, 2)
|
|
WHERE price_rub IS NOT NULL
|
|
AND total_area IS NOT NULL
|
|
AND total_area > 0
|
|
AND (price_per_m2 IS NULL OR price_per_m2 = 0);
|
|
|
|
-- ── Pass 2: sale_graph proxy (latest snapshot, type='apartments') ─────────────
|
|
-- domrf_kn_sale_graph.price_avg is the average contract ₽/м² reported by DOM.RF
|
|
-- for the object in a given month. We use the most recent snapshot's average
|
|
-- across all apartment sub-rows as a reasonable object-level proxy.
|
|
WITH sg_latest AS (
|
|
SELECT obj_id,
|
|
AVG(price_avg) AS avg_ppm2
|
|
FROM public.domrf_kn_sale_graph
|
|
WHERE type = 'apartments'
|
|
AND price_avg > 50000
|
|
AND snapshot_date = (
|
|
SELECT MAX(snapshot_date)
|
|
FROM public.domrf_kn_sale_graph
|
|
WHERE type = 'apartments'
|
|
)
|
|
GROUP BY obj_id
|
|
)
|
|
UPDATE public.domrf_kn_flats f
|
|
SET price_per_m2 = ROUND(sg.avg_ppm2, 2)
|
|
FROM sg_latest sg
|
|
WHERE f.obj_id = sg.obj_id
|
|
AND f.price_per_m2 IS NULL;
|
|
|
|
-- ── Pass 3: peer median from free/sold/booked flats in same obj ───────────────
|
|
-- Fallback for objects absent from sale_graph: compute the object-level median
|
|
-- from the priced (status IS NOT NULL) flats in the same building.
|
|
WITH peer AS (
|
|
SELECT obj_id,
|
|
PERCENTILE_CONT(0.5) WITHIN GROUP (ORDER BY price_per_m2) AS median_ppm2
|
|
FROM public.domrf_kn_flats
|
|
WHERE status IS NOT NULL
|
|
AND price_per_m2 IS NOT NULL
|
|
AND price_per_m2 > 0
|
|
GROUP BY obj_id
|
|
)
|
|
UPDATE public.domrf_kn_flats f
|
|
SET price_per_m2 = ROUND(p.median_ppm2::numeric, 2)
|
|
FROM peer p
|
|
WHERE f.obj_id = p.obj_id
|
|
AND f.price_per_m2 IS NULL;
|
|
|
|
COMMIT;
|