MySQL 事件 .csv 输出文件，名称中带有时间戳

Question

我有一个带有 3 个表（日志数据）的 MySQL 数据库。每个表都有相同的结构。

现在我想编写一个每 6 个月运行一次的事件，并导出 csv 文件中的所有行，这些行超过半年并在第二个删除它们。文件名应包含导出的时间戳。

一开始我尝试用静态名称导出一个表 - 效果很好（这里用更小的时间间隔进行测试）：

CREATE EVENT exportLog
ON SCHEDULE
EVERY 1 MINUTE
DO
SELECT *
INTO OUTFILE 'C:/ProgramData/MySQL/MySQL Server 5.7/Uploads/exporttest.csv'
FIELDS TERMINATED BY ','
ENCLOSED BY '"'
ESCAPED BY '\\'
LINES TERMINATED BY '\n'
FROM mytable WHERE timestamp < (NOW() - INTERVAL 5 DAY)

现在我尝试使用包含导出时间戳的动态文件名来处理这个问题。因此，旧文件也永远不会被覆盖。但这不起作用。有人可以帮忙吗？

CREATE EVENT exportLog
ON SCHEDULE
EVERY 1 MINUTE
DO
BEGIN
SET @sql_stmt := concat("SELECT * FROM logtable INTO OUTFILE 'C:/ProgramData/MySQL/MySQL Server 5.7/Uploads/export_", DATE_FORMAT(now(),'%Y-%m-%d %H%i%s'),".csv'");
PREPARE extrct FROM @sql_stmt;
EXECUTE extrct;
DEALLOCATE PREPARE extrct;
END $$
DELIMITER;

感谢您的帮助！

Answer 1

DELIMITER $$
drop event if exists exportLog  $$
CREATE EVENT exportLog
ON SCHEDULE
EVERY 1 MINUTE
DO
BEGIN
declare cnt tinyint(1) default 1;
    table_loop: LOOP
        SET @sql_stmt := concat("SELECT *  INTO OUTFILE 'C:/ProgramData/MySQL/MySQL Server 5.7/Uploads/export_", elt(cnt, 'logtable', 'logtable1', 'logtable2'), DATE_FORMAT(now(),'%Y-%m-%d %H%i%s'),".csv' FIELDS TERMINATED BY ',' ENCLOSED BY '\"' ESCAPED BY '\\\\' LINES TERMINATED BY '\\n' FROM ", elt(cnt, 'logtable', 'logtable1', 'logtable2'));
        PREPARE extrct FROM @sql_stmt;
        EXECUTE extrct;
        DEALLOCATE PREPARE extrct;
        SET cnt = cnt + 1;

        IF cnt < 4 THEN
          ITERATE table_loop;
        END IF;
        LEAVE table_loop;
    END LOOP table_loop;

END $$
DELIMITER ;