Under one mysql instance, two database schemas, how to join tables cross schemas

[songcheng1658]

I have a mysql database with 2 schemas: schema_a, schema_b; How to config sharding sphere to support:

select * from schema_a.table_a a join schema_b.table_b b on a.id=b.id;

[zihaoAK47]

Hello, you can try using federated querying to address the issue. You can refer to the documentation for relevant configuration guidance.

https://shardingsphere.apache.org/document/current/en/features/sql-federation/

[songcheng1658]

Hello, you can try using federated querying to address the issue. You can refer to the documentation for relevant configuration guidance.

https://shardingsphere.apache.org/document/current/en/features/sql-federation/

感谢你的回复；我还有问题

我尝试了【联邦查询】，发现有报错，有坑； 但是我的问题是，我在【一个msyql实例】上的【两个database数据库】； 程序没有能够识别出这个情况，还是要走【联邦查询】； 为什么，不能自动识别是在一个【数据库实例】，直接用mysql的【跨库能力】； 这样起码能解决，我们这种，只有【一个数据库实例】，【多个库】，从而利用mysql的本地跨库能力； 或者是我还没配置好，所以sharding sphere没有能够识别出这种场景

I tried [Federal Query] and found that there were errors and pitfalls; But my problem is that I have [two database databases] on [one msyql instance]; The program failed to recognize this situation and still has to go to [Federal Query]; Why, it cannot be automatically recognized that it is in a [database instance], directly use mysql's [cross-database capability]; This can at least solve the problem. We only have [one database instance] and [multiple libraries], so we can take advantage of MySQL's local cross-database capabilities; Or maybe I haven't configured it yet, so sharding sphere is not able to recognize this scenario.

[github-actions[bot]]

There hasn't been any activity on this issue recently, and in order to prioritize active issues, it will be marked as stale.

[terrymanu]

I don't think "library" is a concept related to ShardingSphere. Due to the high cost of understanding, please allow me to close this issue.