从表中删除孤儿

本文介绍了从表中删除孤儿的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！ 问题描述

我正在清理一张桌子，里面有很多孤立的项目.

I am trying to clean up a table where there are quite a few orphaned items.

我通过查找空值来检查是否与另一个表存在关系来解决这个问题.

I am approaching this by checking to see if there is a relationship to another table by looking for null values.

DELETE FROM table1 LEFT JOIN table2 ON table1.ID = table2.ID WHERE table2.ID IS NULL

我收到一个错误，指出左外连接无效.

I get an error that the left outer join is not valid.

我正在寻找其他方法的建议，以便我可以从这个破裂的关系中删除这些孤儿

I am looking for suggestions on other ways that I can delete these orphans from this broken relationship

推荐答案

试试这个:

DELETE FROM table1 WHERE NOT EXISTS (SELECT NULL FROM table2 WHERE table1.ID = table2.ID)