这种说法适用于：
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 ;每当向表registrations添加新行时，我想设置一个触发器来执行相同的操作（仅针对一行）
我试过这个密码
创建触发器 lookup_player 插入之前 registrations 每行更新注册
设置
新的。 Player Last =players.player\u最后，
新的。 Player First =players.player\u first，new.registrations。 Player Gender =玩家性别，
new.player\u dob=players.date\u出生日期
其中new.aa\u player\u id=players.a\u player\u id；
但我在注册中添加新行时出错
1054-“where子句”中的未知列“players.a\u player\u id”
但这个专栏确实存在
1条答案
按热度按时间yyyllmsg1#
我想出来了
插入之前
registrations每行设置
新的。
Player Last=（从players where new.aa\u player\u id=players.a\u player\u id中选择players.player\u last），新的。
Player First=（首先从players where new.aa\u player\u id=players.a\u player\u id中选择players.player\u），新的。
Player Gender=（从players where new.aa\u player\u id=players.a\u player\u id中选择players.gender），new.player\u dob=（从players where new.aa\u player\u id=players.a\u player\u id中选择players.date\u of\u birth）；