Rails 3.x如何编写基于行值的更新？ [英] Rails 3.x How to write update all based on row value?

问题描述

我希望在添加列后（在同一行中使用现有列值更新新字段）在迁移文件中执行以下SQL查询

I would like the following SQL query to be executed in a migration file after adding a column (updating the new field with existing column value from the same row)

UPDATE users SET last_login=updated_at;

在数据库上执行时，SQL语句正常工作，但是在Rails中，我使用ActiveRecord尝试了多种语法update_all方法但未成功

The SQL statements work properly when executed on the database, but in rails I tried multiple syntax using the ActiveRecord update_all method but without success

User.update_all("last_login=updated_at")

我收到以下错误

ActiveRecord::StatementInvalid: PGError: ERROR:  current transaction is aborted, commands ignored until end of transaction block
: UPDATE "users" SET last_login=updated_at

显然我的语法中缺少某些内容，但无法弄清楚是什么。
谁能指出我正确的语法吗？

Obviously something is missing in my syntax, but can't figure out what. Can anyone point me to the right syntax?

致谢/ J。

推荐答案

语法确实正确，问题在于我必须回滚以前的交易。

Syntax is indeed correct, the issue was relying in the fact that I had to rollback the previous transaction.

User.update_all("last_login=updated_at")

此语句正常工作。

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