MYSQL使用group by结果中的AVG值设置列值

SELECT column1, AVG(column2) AS avg_value
FROM table_name
GROUP BY column1;

UPDATE table_name
SET column3 = (
    SELECT avg_value
    FROM (
        SELECT column1, AVG(column2) AS avg_value
        FROM table_name
        GROUP BY column1
    ) AS subquery
    WHERE subquery.column1 = table_name.column1
);

CREATE TEMPORARY TABLE temp_table
SELECT column1, AVG(column2) AS avg_value
FROM table_name
GROUP BY column1;

UPDATE table_name
JOIN temp_table ON table_name.column1 = temp_table.column1
SET table_name.column3 = temp_table.avg_value;

DROP TEMPORARY TABLE temp_table;