SQL 更新时将旧数据保存到另一个 table

Question

我有两个 table：players 和 history_of_players。

我想为球员创造某种历史，所以如果有人在球员 table 中更新 'club'，我希望将旧数据（旧俱乐部）保存到 [=15] =] 与 'player_ID'、'old_club' 和 'year'（实际年份）。

Answer 1

有一段时间没有使用 MySQL 但这应该是您正在寻找的（如果播放器中始终只有一行 table 每个 player_ID） :

delimiter //
CREATE TRIGGER historise BEFORE UPDATE ON players
  FOR EACH ROW
     BEGIN
       INSERT INTO history_of_players (player_ID, old_club, year)
       SELECT player_ID, old_club, year FROM players
       WHERE player_ID = OLD.player_ID;
     END;//
delimiter ;

Answer 2

您可能希望在 players table 上创建触发器。例如：

DELIMITER $$
CREATE TRIGGER playersHistoryTrigger
AFTER UPDATE ON players
FOR EACH ROW BEGIN
    INSERT INTO playersHistory
    VALUES (NEW.ID, NEW.Name, ...);
END$$
DELIMITER ;

Answer 3

这可以通过触发器来完成。

delimiter //
CREATE TRIGGER playerup BEFORE UPDATE ON players
    FOR EACH ROW
    BEGIN
        INSERT INTO history_of_players (player_ID, old_club, date)
        VALUES (NEW.player_ID, OLD.club, CURDATE());
    END;//

SQL 更新时将旧数据保存到另一个 table

SQL on UPDATE save old data into another table

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