PostgreSQL:如何构建一个每日合计不断增加的表？

CREATE TABLE daily_totals (
    date DATE PRIMARY KEY,
    total INTEGER
);

CREATE OR REPLACE FUNCTION update_daily_total()
RETURNS TRIGGER AS $$
BEGIN
    -- 获取当前日期
    DECLARE current_date DATE := CURRENT_DATE;
    
    -- 检查每日合计表中是否已存在当前日期的记录
    IF EXISTS (SELECT 1 FROM daily_totals WHERE date = current_date) THEN
        -- 更新合计值
        UPDATE daily_totals SET total = total + NEW.value WHERE date = current_date;
    ELSE
        -- 插入新的记录
        INSERT INTO daily_totals (date, total) VALUES (current_date, NEW.value);
    END IF;
    
    RETURN NEW;
END;
$$ LANGUAGE plpgsql;

CREATE TRIGGER update_daily_total_trigger
AFTER INSERT ON original_table
FOR EACH ROW
EXECUTE FUNCTION update_daily_total();

CREATE EXTENSION pg_cron;

SELECT cron.schedule('0 0 * * *', 'TRUNCATE TABLE original_table');