There's an unexpected behavior with composite keys mapped with @Id and Many-To-Many associations mapped as 2 Many-To-Ones.

I've create a test case:

Have a look at the entities: https://github.com/michael-simons/possible_hibernate_426_bug_with_date/tree/master/src/main/java/entities

A1

and the same with "2".

Ax has a composite key that also references another Entity foobar which is - i hope - jpa conform. Please ignore that on MySQL the primary key is only defined as id, i wanted to use an auto-increment for id.

The only difference from the mappings is the naming of the id attribute in Ax.

In A1 it's called "id" and in A2 it's called "a2id".

When i run https://github.com/michael-simons/possible_hibernate_426_bug_with_date/blob/master/src/test/java/tests/IdColumnNamesTest.java the CriteriaQuery with a subquery (all Ax's that have a Bx) fails for the "1" entities with

"Caused by: java.sql.SQLException: Operand should contain 2 column(s)" on mysql and with

"SqlNode's text did not reference expected number of columns" on Oracle.

The A2 case where id has a different name works as expected (with the correct results in production).