Try by having an inverse edge on Product:
type Product {
...
reviews: [Review] @hasInverse(field: productID)
}
Then you could do:
query {
getProduct(id: '0x1') {
reviews {
id
userId
...
}
}
Otherwise you get into the nested filter territory, which you can’t yet do in GraphQL. The workaround is custom dql, which you would have to learn as a separate query language.
J