Question

此语句有效：

UPDATE 
    registrations 
    JOIN players ON registrations.aa_player_id = players.a_player_id 
SET 
    registrations.`Player First`=players.player_first,    
    registrations.`Player Last`=players.player_last,    
    registrations.`Player Gender`=players.gender,
    players.date_of_birth=registrations.player_dob ;

每当将新行添加到表 registrations

中时，我都希望设置一个触发器以执行相同的操作（仅针对一行）

我已经尝试过此代码

创建触发器lookup_player
在registrations上插入之前
每行更新注册

设置
    new。Player Last = players.player_last，
    新增。Player First = players.player_first，      new.registrations。Player Gender = players.gender，
    new.player_dob = players.date_of_birth
  其中new.aa_player_id = players.a_player_id;

但是当我向注册

添加新行时出现错误

1054-“ where子句”中的未知列“ players.a_player_id”

但是那列确实存在

Answer 1

想通了

CREATE  TRIGGER `lookup player`

在registrations上插入之前    每行
   设置
   new。Player Last =（从有new.aa_player_id = players.a_player_id的玩家中选择players.player_last），
   new Player First =（从有new.aa_player_id = players.a_player_id的玩家中选择players.player_first），
   new。Player Gender =（从有new.aa_player_id = players.a_player_id的玩家中选择player.gender），
   new.player_dob =（从new.aa_player_id = players.a_player_id的玩家中选择players.date_of_birth）；

MySQL-在插入时从相关表中插入值？

1 个答案: