[ { father => 'person', -join_type => 'inner' }, { 'father.person_id' => 'child.father_id' }, ],
[ { mother => 'person', -join_type => 'inner' }, { 'mother.person_id' => 'child.mother_id' } ],
);
-$match = 'person child INNER JOIN person father ON ( father.person_id = '
- . 'child.father_id ) INNER JOIN person mother ON ( mother.person_id '
+$match = 'person child JOIN person father ON ( father.person_id = '
+ . 'child.father_id ) JOIN person mother ON ( mother.person_id '
. '= child.mother_id )'
;