创建一个存储过程，用一行填充一个表--每年和每月的平均值

CREATE PROCEDURE calculate_avg()
BEGIN
    -- 创建用于存放结果的表
    CREATE TABLE IF NOT EXISTS avg_table (
        year INT,
        month INT,
        average DECIMAL(10, 2)
    );

    -- 清空表中的数据，如果表中已存在数据的话
    DELETE FROM avg_table;

    -- 计算每年平均值并插入表中
    INSERT INTO avg_table (year, average)
    SELECT YEAR(date_column) AS year, AVG(value_column) AS average
    FROM your_table
    GROUP BY YEAR(date_column);

    -- 计算每月平均值并插入表中
    INSERT INTO avg_table (year, month, average)
    SELECT YEAR(date_column) AS year, MONTH(date_column) AS month, AVG(value_column) AS average
    FROM your_table
    GROUP BY YEAR(date_column), MONTH(date_column);
END;