ToolJet/docs/versioned_docs/version-2.33.0/data-sources/clickhouse.md

---
id: clickhouse
title: ClickHouse
---

# ClickHouse

ToolJet can connect to the ClickHouse to read and write data.

:::info
ToolJet uses this [NodeJS](https://github.com/TimonKK/clickhouse) client for ClickHouse.
:::

## Connection

To establish a connection with the Clickhouse data source, you can either click on the `+Add new data source` button located on the query panel or navigate to the **[Data Sources](/docs/data-sources/overview)** page through the ToolJet dashboard.

ToolJet requires the following to connect to your ClickHouse Database:

- **Username**
- **Password**
- **Host**
- **Port**
- **Database Name**
- **Protocol**
- **Use Post**
- **Trim Query**
- **Use Gzip**
- **Debug**
- **Raw**

<img className="screenshot-full" src="/img/datasource-reference/clickhouse/connection-v2.png" alt="ClickHouse connection" />

## Querying ClickHouse

After setting up the ClickHouse data source, you can click on the `+` button of the query manager and select the ClickHouse data source that you added in the previous step to create a new query.

:::info
For more details on clickhouse visit [Clickhouse docs](https://clickhouse.com/docs/en/quick-start).
:::

## Supported Operations:

- [SQL Query](#sql-query)
- [Insert array of objects](#supported-operations)

### SQL Query

Use this to operation to enter **[ClickHouse SQL Statements](https://clickhouse.com/docs/en/sql-reference/statements/)**. These statements represent various kinds of action you can perform using SQL queries.

#### Example SQL queries

- **SELECT**:

  ```sql
  SELECT * from test array;
  ```

  <div style={{textAlign: 'center'}}>

  <img className="screenshot-full" src="/img/datasource-reference/clickhouse/select.png" alt="ClickHouse SQL Statement operation" />

  </div>

- **CREATE**:

  ```sql
  CREATE TABLE test array3 (
  	date Date,
  	str String,
  	arr Array(String),
  	arr2 Array (Date)
  	arr3 Array(UInt32) ,
  	id1 UUID
  )ENGINE=MergeTree () ORDER BY(str)
  ```

  <div style={{textAlign: 'center'}}>

  <img className="screenshot-full" src="/img/datasource-reference/clickhouse/create.png" alt="ClickHouse SQL Statement operation" />

  </div>

- **ALTER TABLE**(add column)

  ```sql
  ALTER TABLE test array1 ADD COLUMN Added2 UInt32;
  ```

  <div style={{textAlign: 'center'}}>

  <img className="screenshot-full" src="/img/datasource-reference/clickhouse/alter.png" alt="ClickHouse SQL Statement operation" />

  </div>

- **SELECT WITH WHERE CLAUSE**

  ```sql
  SELECT * FROM test array1 WHERE str='Somethingl...'
  ```

  <div style={{textAlign: 'center'}}>

  <img className="screenshot-full" src="/img/datasource-reference/clickhouse/selectwithwhere.png" alt="ClickHouse SQL Statement operation" />

  </div>

- **UPDATE**

  ```sql
  ALTER TABLE test_array1 UPDATE arr = (12] WHERE str='Somethingl...'
  ```

  <div style={{textAlign: 'center'}}>

  <img className="screenshot-full" src="/img/datasource-reference/clickhouse/update.png" alt="ClickHouse SQL Statement operation" />

  </div>

- **DELETE**

  ```sql
  ALTER TABLE test_array1 DELETE WHERE str= 'Somethingl...'
  ```

  <div style={{textAlign: 'center'}}>

  <img className="screenshot-full" src="/img/datasource-reference/clickhouse/delete.png" alt="ClickHouse SQL Statement operation" />

  </div>

- **NORMAL INSERT**

  1.  Step 1 - Creating Table

  ```sql
  CREATE TABLE test array4 (
  name String,
  date Date
   )ENGINE=MergeTree () ORDER BY (name)
  ```

  <div style={{textAlign: 'center'}}>

  <img className="screenshot-full" src="/img/datasource-reference/clickhouse/step1.png" alt="ClickHouse SQL Statement operation" />

  </div>

  2.  Step 2 - Insert

  ```sql
  INSERT INTO test_array4 (*) VALUES ('juvane', '1996-01-13')
  ```

  <div style={{textAlign: 'center'}}>

  <img className="screenshot-full" src="/img/datasource-reference/clickhouse/step1.png" alt="ClickHouse SQL Statement operation" />

  </div>

  :::info
  **Giving Primary Key**

  ```
  CREATE TABLE db.table_name
  (
  	name1 type1, name2 type2, ...,
  	PRIMARY KEY(expr1[, expr2,...])]
  )
  ENGINE = engine;

  OR

  CREATE TABLE db.table_name
  (
  	name1 type1, name2 type2, ...
  )
  ENGINE = engine
  PRIMARY KEY(expr1[, expr2,...]);
  ```

  :::

### Insert array of objects

Use this operation for inserting array of objects.

#### Required Parameters:

- **Body**
- **Fields**
- **Table name**

**Example Body value:**

```javascript
[
  {
    date: "2018-01-01",
    str: "Something1...",
    arr: [],
    arr2: ["1985-01-02", "1985-01-03"],
    arr3: [1, 2, 3, 4, 5],
    id1: "102a05cb-8aaf-4f11-a442-20c3558e4384",
  },
  {
    date: "2018-02-01",
    str: "Something2...",
    arr: ["5670000000", "Something3..."],
    arr2: ["1985-02-02"],
    arr3: [],
    id1: "c2103985-9a1e-4f4a-b288-b292b5209de1",
  },
];
```

<img className="screenshot-full" src="/img/datasource-reference/clickhouse/insertarray.png" alt="ClickHouse Insert array of objects operation" />