How to load data from SFTP Bulk to Clickhouse

Begin by ensuring you have secure access to the SFTP server. You will need the hostname, port, username, and password (or SSH key) to log in. Use an SFTP client or command-line tool like `sftp` or `scp` to test your connection and navigate the directory structure of the SFTP server.

Determine which files you need to transfer to ClickHouse. Use the SFTP command-line tool to list files and directories. Once identified, download the necessary files to your local system or a temporary server by using the `get` command in your SFTP session.

Ensure your local environment or the temporary server where the files are downloaded has ClickHouse installed and running. This involves setting up ClickHouse Server and ClickHouse Client, which can be done by following the official ClickHouse documentation for your specific operating system.

Before importing data into ClickHouse, inspect the files for any inconsistencies or issues. Use tools like `awk`, `sed`, or `grep` for text processing and cleaning if needed. Ensure the data format aligns with the schema you plan to use in ClickHouse.

Create a table in ClickHouse that matches the structure of your data. Use the ClickHouse Client to execute `CREATE TABLE` statements. Ensure the data types and column names correspond to the fields in your data files. Example:
```sql
CREATE TABLE my_table (
id UInt32,
name String,
date Date
) ENGINE = MergeTree()
ORDER BY id;
```

Use the ClickHouse Client to import data from the local files. You can use the `cat` command piped into the ClickHouse Client for bulk inserts. For example:
```bash
cat datafile.csv | clickhouse-client --query="INSERT INTO my_table FORMAT CSV"
```
Ensure the file format specified matches your data file format (e.g., CSV, TSV).

After the data import, verify that the data has been correctly transferred. Use queries in the ClickHouse Client to check the number of records, perform sample queries, and ensure data integrity. Example:
```sql
SELECT COUNT(*) FROM my_table;
```
Adjust your data cleaning or import process if discrepancies are found.

By following these steps, you should be able to successfully and directly move data from an SFTP server into a ClickHouse warehouse without using third-party connectors or integrations.