# Join two datasets by a key field, like VLOOKUP

**Use case:** 

Adds fields from a lookup dataset (for example a product or supplier list) to every item of your datasets that has the same key value, like VLOOKUP in a spreadsheet. Choose a left join to keep items without a match, or an inner join to keep only matches. Key values can be matched loosely: spaces, upper and lower case, full-width and half-width characters, katakana and hiragana.

## Input

```json
{
  "removeDuplicates": true,
  "keep": "first",
  "joinType": "inner",
  "lookupPrefix": "lookup_",
  "keyNormalization": [
    "trim",
    "case",
    "width",
    "kana"
  ],
  "addSourceDataset": false,
  "addDuplicateCount": false
}
```

## Output

```json
{
  "sku": {
    "label": "Sku"
  },
  "name": {
    "label": "Name"
  },
  "maker": {
    "label": "Maker"
  },
  "price": {
    "label": "Price"
  },
  "currency": {
    "label": "Currency"
  },
  "url": {
    "label": "Url"
  },
  "maker_country": {
    "label": "Maker country"
  },
  "maker_supportEmail": {
    "label": "Maker support email"
  },
  "maker_leadTimeDays": {
    "label": "Maker lead time days"
  },
  "_sourceDataset": {
    "label": "Source dataset"
  },
  "_duplicateCount": {
    "label": "Duplicate count"
  }
}
```

## How it works

### 1. Sign up on Apify or log in

The Merge, Deduplicate & Join Datasets Actor is ready to run with the inputs already set for "Join two datasets by a key field, like VLOOKUP". [Sign up or log in](https://console.apify.com/create-task-from-example/aD9TOyoe451ygH6Zk) and you'll land in Apify Console with a copy of this exact task.

### 2. Start the "Join two datasets by a key field, like VLOOKUP" task

The Merge, Deduplicate & Join Datasets Actor will start running based on the input automatically. You can also change all the input fields, like remove duplicates, which duplicate to keep, and more, to match your specific use case.

### 3. Receive the "Join two datasets by a key field, like VLOOKUP" output

Monitor the progress in real time. You will be notified as soon as your dataset is complete and ready for review. Each result includes data such as sku, name, maker, and more.

### 4. Integrate into your workflow

The final output is delivered in JSON, CSV, or Excel format, ready to be plugged into your workflow. You can also [run the "Join two datasets by a key field, like VLOOKUP" task via API](https://apify.com/quietworkslab/merge-dedup-datasets.md).

## FAQ

### What happens when the lookup dataset has the same key twice?

The VLOOKUP join task uses the first lookup item for each key and logs how many later lookup items had a key that appeared before. One item never produces more than one output row.

### Do lookup fields overwrite my own fields?

No. The VLOOKUP join task adds lookup fields with a prefix (lookup_ by default), and if a field name is still taken, the item keeps its own value and the run logs the clash.

### How much does merging datasets cost?

The Merge, Deduplicate & Join Datasets Actor charges $0.0001 per item read ($0.10 per 1,000 items) and one item per started 20 items of a lookup dataset, plus Apify's Actor start event. The built-in sample is not charged per item.

## About this Actor

This example demonstrates how to use [Merge, Deduplicate & Join Datasets](https://apify.com/quietworkslab/merge-dedup-datasets.md) with a specific input configuration. Visit the [Actor detail page](https://apify.com/quietworkslab/merge-dedup-datasets.md) to learn more, explore other use cases, and run it yourself.


## How to integrate an Actor?

This Task's input is already configured above. Use it as-is rather than inventing a new one.

Do not guess an integration path. Every one of them is in the agent quickstart at https://apify.com/agents.md: the Apify MCP server, Agent Skills with the Apify CLI, the JavaScript and Python clients, the REST API, and the account-free path for an agent with no human to sign in. It also carries the rule on stating cost before the first paid run.

For full API examples (JavaScript, Python, CLI, MCP, OpenAPI), see this Task's Actor page: https://apify.com/quietworkslab/merge-dedup-datasets.md

Each client library has reference documentation the quickstart does not restate: [JavaScript/TypeScript](https://docs.apify.com/api/client/js/docs.md) (`npm install apify-client`) and [Python](https://docs.apify.com/api/client/python/docs.md) (`pip install apify-client`).