How to join tables with a array of IDs

Question

Attempting to use this example to join on an array of IDs: https://github.com/rethinkdb/rethinkdb/issues/1533#issuecomment-26112118

Stores table snippet

Answer 1

You're using concatMap incorrectly, here's what you want the first part of your query to be.

r.table("stores")
 .concatMap(function (x) {
   return x("locations");
 })

Try running that, it should give you:

["5fa96762-...", "80362c86-...", ...]

Now we need to join this to the other table. To join an array of ids to a table you can use eqjoin like so:

array.eqJoin(function (row) { return row; }, table)

There's more details here: rql get multple documents from list of keys rethinkdb in javascript.

Putting it all together we get:

r.table("stores")
 .concatMap(function (x) {
   return x("locations")
 })
 .eqJoin(function (i) { return i; }, r.table("locations"))

---

To get back the documents from the stores:

r.table("stores")
 .concatMap(function (x) {
   return x("locations").map(function (loc) {
      return x.merge({locations: loc});
   });
 })
 .eqJoin("locations", r.table("locations"))