[Sqlalchemy-tickets] Issue #3546: Query object having multiple entities fails when trying to join (zzzeek/sqlalchemy)

[Andrey S. <iss...@bi...>]

New issue 3546: Query object having multiple entities fails when trying to join
https://bitbucket.org/zzzeek/sqlalchemy/issues/3546/query-object-having-multiple-entities

Andrey Semenov:


```
#!python

Session.query(Address, Order, OrderLog).outerjoin(OrderLog, Order.id == OrderLog.order_id)
```
This code produces a query like:


```
#!SQL
SELECT ...
FROM orders, addresses LEFT OUTER JOIN order_logs ON orders.id = order_logs.order_id
```
This leads to an error at server side:

```
#!text

ProgrammingError: (psycopg2.ProgrammingError) invalid reference to FROM-clause entry for table "orders"
LINE 3: ...M orders, addresses LEFT OUTER JOIN order_logs ON orders.id ...
                                                             ^
```

so, the autowiring joins (auto-grouping them by entity relationship given at join_clauses) does not work. The docs don't say how to explicitly point the left part of join.

The query I'm trying to build up is like:

```
#!SQL

SELECT ...

FROM entity_1 JOIN entity_1_1 ON ..., entity_2 JOIN entity_2_1 ON ..., entity_3, entity_4 JOIN entity_4_1 ON ...
```

Current query builder chains all .join() of Query objects to the first entity of the `_entities` list