RethinkDB - Left join where joined_table.identifier is null? -

i have 2 tables in rethinkdb database represent one-to-many relationship. consider following 2 tables:

t1 parentid    name 1           lorem 2           ipsum 3           dotor 4           sit 5           amet  t2 childid parentid    childname 1       1           2       3           random 3       5           here 

on t1, parentid primary key, , on t2, there secondary index on parentid. want find parents don't have child. operation in sql (mssql exact) looks this:

select t1.* t1 left outer join t2 on t2.parentid = t1.parentid t2.childid null  results: parentid    name 2           ipsum 4           sit 

how can accomplish similar result in rethinkdb? thank you!

i this:

r.table('t1').filter(function(parent) {   return r.table('t2').get_all(parent('parentid'), {index: 'parentid'}).count().eq(0); })