Hi,

Odoo intentionally avoids LEFT JOINs in views like Sales Orders to keep queries simpler, modular, and avoid issues like row duplication in one-to-many or many-to-many relationships.

Instead, it uses a prefetching mechanism that batches related record queries efficiently and caches them for reuse, reducing the total number of queries during record navigation.

This design helps maintain better form view performance, especially when fields involve access rules or computed values, which can make complex joins slower or problematic.

Although it may look inefficient in profiling tools, this approach generally results in better real-world performance, scalability, and database compatibility, especially with PostgreSQL.

Hope it helps.