MySQL-如果column为null，则从另一个表中检索值 [英] MySQL - retrieve a value from another table if column is null

问题描述

比方说，我有一个表设置，其中包含一些值，包括名称，ID和引用另一个表ID的外键.名称可以为空.当我从该表中选择所有记录时，如果名称不为null，我想获取名称.如果是这样，我想获取外键引用的记录的名称.我可以根据需要修改数据库结构，也可以简单地更改查询.我有什么选择?

Let's say I have a table setup with a few values, including a name, an ID, and a foreign key that references the ID of another table. The name can be null. When I select all the records from this table, I want to get the name if it is not null. If it is, I want to get the name of the record referenced by the foreign key. I am able to modify the database structure if necessary, or I can simply change the query. What are my options?

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