期間マスタからのデータの取得方法

WITH current_date AS (
    SELECT CURRENT_DATE AS today
),
current_fiscal_year AS (
    SELECT
        CASE
            WHEN EXTRACT(MONTH FROM today) >= 4 THEN EXTRACT(YEAR FROM today)
            ELSE EXTRACT(YEAR FROM today) - 1
        END AS fiscal_year_start
    FROM current_date
),
fiscal_year_dates AS (
    SELECT
        fiscal_year_start,
        TO_DATE(fiscal_year_start || '-04-01', 'YYYY-MM-DD') AS fiscal_year_start_date,
        TO_DATE((fiscal_year_start + 1) || '-03-31', 'YYYY-MM-DD') AS fiscal_year_end_date
    FROM current_fiscal_year
)
SELECT *
FROM period_master pm
JOIN fiscal_year_dates fyd
ON (pm.start_date <= fyd.fiscal_year_end_date AND pm.end_date >= fyd.fiscal_year_start_date);