How to use StreamingApi MultiFieldComparator?

[Markko Legonkov]

Hi

What i would like to achieve is that i want to filter out all products
which have different prices on two given dates.
Here is a sample expression

leftOuterJoin(
  search(
    products,
    q="*:*",
    fq="product_id_i:1 AND product_name_s:test",
    fl="id, product_id_i, product_name_s,sale_price_d",
    sort="product_id_i asc"
  ),
  select(
    search(
      products,
      q="product_id_i:1 AND product_name_s:Test",
      fl="id, product_id_i, product_name_s,sale_price_d",
      sort="product_id_i asc"
    ),
    id as c_id,
    product_id_i as c_product_id_i,
    product_name_s as c_product_name_s,
    sale_price_d as c_sale_price_d
  ),
  on="product_id_i=c_product_id_i, sale_price_d!=c_sale_price_d"
)

I am using solr 6.2.0
And the result i get from solr is:
{
  "result-set": {
    "docs": [
      {
        "EXCEPTION": "org.apache.solr.client.solrj.io.comp.FieldComparator
cannot be cast to
org.apache.solr.client.solrj.io.comp.MultipleFieldComparator",
        "EOF": true
      }
    ]
  }
}

Do i have to configure something in solr that it knows it has to use
MultipleFieldComparator?

Regards
Max