[Feature][Sort] Support multi node relation with same output but different input nodes

[EMsnap]

Description

Now it's not capable for sort to generate multi insert sqls for one output with multiple inputs which is not acceptable for user cases.

For instance, user may want to get data from multiple data sources, they can only use union operation for now. But union operation in flink is too heavy.

We need to support generate sqls from one stream such that:

Insert into sink select * from sourceA;
Insert into sink select * from sourceB;

Use case

We need to support generate sqls from one stream such that:

Insert into sink select * from sourceA;
Insert into sink select * from sourceB;

Are you willing to submit PR?

• Yes, I am willing to submit a PR!

Code of Conduct

• I agree to follow this project's Code of Conduct