Question

我试图在表1插入数据之前使用触发器将table2中的值复制到table1，我遇到的问题是每当我向table1插入一个新行时，我都会收到一条错误消息，说明该列可以不是，在我的情况下，列是颜色。只是fyi表1有一个名为'color'的列以及表2

这是我的代码

CREATE 
TRIGGER `some_trigger` BEFORE INSERT ON `table1`
FOR EACH ROW BEGIN
SET new.color = 
(
    SELECT table2.color
    FROM table1
    JOIN table2 ON table1.aforeignkeycolumn = table2.aprimarykeycolumn
    WHERE table1.id = new.id  --this should be the new row
);
END;

如果我有这个它会工作，但我需要获得将要插入表1的行的ID

CREATE 
TRIGGER `some_trigger` BEFORE INSERT ON `table1`
FOR EACH ROW BEGIN
SET new.color = 
(
    SELECT table2.color
    FROM table1
    JOIN table2 ON table1.aforeignkeycolumn = table2.aprimarykeycolumn
    WHERE table1.id = 10
);
END;

感谢任何帮助

Answer 1

插入触发后执行怎么样？

CREATE TRIGGER `some_trigger` AFTER INSERT ON `table1` FOR EACH ROW BEGIN SELECT new.color := table2.color FROM table1 JOIN table2 ON table1.aforeignkeycolumn = table2.aprimarykeycolumn WHERE table1.id = new.id --this should be the new row END;

从一个表到另一个表的mysql复制值给我错误

1 个答案: