How to load data from ClickHouse to MySQL Destination

Begin by ensuring the data you want to transfer is ready for export. You might need to perform any necessary data transformations or aggregations using SQL queries within ClickHouse to shape your data as needed.

Use ClickHouse's built-in functionality to export your data to a CSV file. Run a SQL query in ClickHouse with the `INTO OUTFILE` clause to export the result to a CSV file:
```sql
SELECT FROM your_table
INTO OUTFILE '/path/to/export.csv'
FORMAT CSV;
```
Ensure you have permissions to write to the specified directory.

Transfer the CSV file from the ClickHouse server to the MySQL server. You can use secure methods like SCP (Secure Copy Protocol) or SFTP (SSH File Transfer Protocol) to transfer the file:
```bash
scp /path/to/export.csv user@mysql-server:/path/to/destination/
```

In MySQL, create a database and a table to accommodate the data you are importing. Make sure the table schema matches the structure of your CSV data:
```sql
CREATE DATABASE my_database;
USE my_database;

CREATE TABLE my_table (
column1 INT,
column2 VARCHAR(255),
...
);
```

Use the `LOAD DATA INFILE` command in MySQL to import the CSV data into your table:
```sql
LOAD DATA INFILE '/path/to/destination/export.csv'
INTO TABLE my_table
FIELDS TERMINATED BY ','
ENCLOSED BY '"'
LINES TERMINATED BY '\n'
IGNORE 1 ROWS;
```
Adjust file path and options like ignoring header rows or setting delimiters according to your CSV format.

After loading the data, verify that the data in MySQL matches the original data in ClickHouse. Perform checks like row count and spot-check specific data points by querying both ClickHouse and MySQL:
```sql
SELECT COUNT() FROM your_table; -- in ClickHouse
SELECT COUNT() FROM my_table; -- in MySQL
```

If you need to perform this transfer regularly, consider scripting the entire process using a shell script or a cron job. This will automate the data export, transfer, and import steps:
```bash
#!/bin/bash
clickhouse-client --query "SELECT FROM your_table INTO OUTFILE '/path/to/export.csv' FORMAT CSV;"
scp /path/to/export.csv user@mysql-server:/path/to/destination/
mysql -u username -p -e "LOAD DATA INFILE '/path/to/destination/export.csv' INTO TABLE my_database.my_table FIELDS TERMINATED BY ',' ENCLOSED BY '\"' LINES TERMINATED BY '\n' IGNORE 1 ROWS;"
```
Schedule this script to run at regular intervals using cron.

By following these steps, you can efficiently and securely transfer data from ClickHouse to MySQL without relying on third-party connectors or integrations.