使い込むほど
精度が上がるDBがある

-- 「最新レースから始まる連続逃げ先行ストリーク本数」を1クエリで抽出
WITH ordered_races AS (
    SELECT s.KETTO_TOROKU_BANGO, r.RACE_DATE, s.CORNER1, s.FIELD_SIZE,
           ROW_NUMBER() OVER (PARTITION BY s.KETTO_TOROKU_BANGO
                              ORDER BY r.RACE_DATE DESC) AS rn
    FROM JRDB_SED s JOIN RACES r ON r.RACE_ID = s.JRDB_RACE_KEY
    WHERE r.RACE_DATE < TO_DATE(:cutoff_date, 'YYYY-MM-DD')
),
front_streaks AS (
    SELECT * FROM ordered_races
    MATCH_RECOGNIZE (          -- ← PostgreSQL未実装
        PARTITION BY KETTO_TOROKU_BANGO ORDER BY rn
        MEASURES  COUNT(*) AS streak_len,  FIRST(rn) AS first_rn
        ONE ROW PER MATCH  AFTER MATCH SKIP PAST LAST ROW
        PATTERN (FRONT+)
        DEFINE  FRONT AS CORNER1 <= 3   -- 1〜3番手通過 = 逃げ/先行
    )
)
SELECT KETTO_TOROKU_BANGO,
       CASE WHEN first_rn = 1 THEN streak_len ELSE 0 END AS consec_front_runs
FROM front_streaks WHERE match_num = 1