[Dbix-class] pick and choose columns with join + collapse

[Seth Daniel]

I have two tables with a many-to-many relationship, say:

Table A    A_B (Join Table)   Table B

Any A can have many B, and any B can be assigned to any A.  All via the
join table. Each of A and B has an 'id' and 'name' column (and likely many
other columns that are unimportant for this example).

If I want to find all A that have any one B assigned to it *and* retrieve
all B for the selected A *and* do this in one query I've been doing this:

my $rs = $s->resultset( 'A' )
           ->search( { 'B.name' => 'some_name' },
                     { prefetch => [ { A_B => 'B' },
                                     { A_B => 'B' } ] } );

I list the prefetch twice. If I only list it once I only get those B that
match the search criteria, instead of all B for the selected A.

I now want to do the same thing, but only return those columns from A and B
that I want.  So I tried this:

my $rs = $s->resultset( 'A' )
           ->search( { 'B.name' => 'some_name' },
                     { columns => [ 'id', { 'A_B.B.name' => 'B.name' } ],
                       collapse => 1,
                       join => [ { A_B => 'B' },
                                 { A_B => 'B' } ] } );

This does return only the columns I ask for, but it also only returns the B
that match the search criteria instead of all B for the selected A.

Is there a way I can get the same results as my first example, but by only
returning the columns like from  my second example?

I've been using DBIx::Class 0.082810.

Thank you.
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