Not sure, if it is good, to have the packageName starting with uppercase.
I think, its better, to have everthing lowercase.
In this case, you can try
[[migxLoopCollection? &packageName=`Catalog` &classname=`Data1` &joins=`[ {"alias":"Data2","classname":"Data2","on":"Data2.model_number=Data1.model_number"}, {"alias":"Data3","classname":"Data3","on":"Data3.model_number=Data1.model_number"} ]` &tpl=`yourTplChunk` &where=`{"Data1.model_number":"themodelnumber"}` ]]
you will have all the Data1-fields without prefix and the other fields with prefix Data1_ and Data2_
If (and it's a big if) you've properly created the tables as related objects of each other, you can use getCollectionGraph() to get them all in a single query. You can also use $query->leftJoin() with getCollection().
Here's getCollectionGraph() example for users that includes the user profile and custom data. In the example, Profile and Data are aliases of the two user-related objects. The result is an array of $userObjects, each with its own $user->Profile and $user->Data object containing the fields for that user from the other tables:
$c = $modx->newQuery('modUser'); $c->sortby('fullname', 'ASC'); $c->where( array('Data.last_name' => 'Johnson'), ); $users = $modx->getCollectionGraph('modUser', '{"Profile":{},"Data":{}}', $c);
In the second argument to getCollectionGraph(), you can have as many related objects as you need in the JSON section.
Remove the $c->where() part of you want all of them.
To process the results you can do something like this (off the top of my head, so possibly not correct):
foreach ($users as $user) { $pFields = $user->Profile->toArray(); $dFields = $user->Data->toArray(); $ufields = $user->toArray(); $allFields = array_merge($pFields, $dFields, $uFields); $output .= $modx->getChunk('MyTpl', $allFields); }
Be sure to put the $user fields as the last argument in the array_merge() so that the user ID will be correct.
