What is the difference between ''join([innerJoin(), innerJoin()])'' and ''join([innerJoin()]).join([innerJoin()]) ''?

[ddxl123]

What is the difference between join([innerJoin(), innerJoin()]) and join([innerJoin()]).join([innerJoin()])?

final sonAndFather = innerJoin( fathers, fathers.sonId.equals( sons.id ));
final matherAndFather = innerJoin( mathers, mathers.fatherId.equals( fathers.id ));
select(sons).join([sonAndFather, matherAndFather]);

MatherAndFather does not use sons to compare with mathers, so is there a problem with the query? If I can't do this query, how do I want to achieve such a query?

[simolus3]

There is no difference. Calling join multiple times will add the joins as well.

MatherAndFather does not use sons to compare with mathers, so is there a problem with the query?

No, this is completely fine! Not all joins have to reference the original table, doing it like this should work. However, there is an optimization opportunity if you don't need all tables in the end. If you only care about some tables in the result (for instance, if you only need sons and mathers and joined fathers for the sole purpose of doing the second join), you can set includeColumns: false on the join to disable including it in the results. Bug again, this is just a matter of optimization - your existing way of writing joins will work fine.