I guess SQLX-core is not yet supported of INSERT RETURNING。
The current solution is to use predefined IDs, such as the snowflake algorithm and object-id. 2 is in the RBatis plugin

Please add support for INSERT RETURNING in PostgreSQL database.

https://www.postgresql.org/docs/9.5/sql-insert.html

It can be

• either for returning new instance of struct filled with fields from DB
• or adding support for last_insert_id through it (there seems to be a discussion about this field in last_insert_id is None #75)

Example:

INSERT INTO distributors (did, dname) VALUES (DEFAULT, 'XYZ Widgets')
   RETURNING did;

see https://github.com/rbatis/rbatis/blob/master/example/src/crud.rs

save_by_wrapper

v4 use impl_select! macro supported