{
  "$schema": "urn:prism:schema:v1:spec",
  "title": "Join two named datasets",
  "datasets": {
    "scores": {
      "values": [
        {"brand_id": "alpha", "score": 0.42},
        {"brand_id": "beta",  "score": 0.71}
      ]
    },
    "labels": {
      "values": [
        {"brand_id": "alpha", "label": "Alpha Inc"},
        {"brand_id": "beta",  "label": "Beta LLC"}
      ]
    }
  },
  "data": {"name": "scores"},
  "transform": [
    {"join": "inner", "with": "labels", "on": "brand_id", "data": "scores", "as": "joined"}
  ],
  "mark": "bar",
  "encoding": {
    "x": {"field": "brand_id", "type": "nominal"},
    "y": {"field": "score",    "type": "quantitative"}
  }
}