Start by exporting your data from Notion. Navigate to the Notion page or database you want to export. Click on the three dots in the upper-right corner and select "Export". Choose "CSV" as the export format since it is a widely supported format for data manipulation and transfer.

Open the exported CSV file in a spreadsheet application like Microsoft Excel or Google Sheets. Review the data to ensure it is correctly formatted and clean up any anomalies. Ensure that the first row contains headers that will match the column names in your MySQL table.

Access your MySQL database using a client like MySQL Workbench or the command line. Create a database if you don't have one yet:
```sql
CREATE DATABASE notion_data;
```
Then create a table structure that matches the CSV file's column headers:
```sql
CREATE TABLE my_table (
column1 VARCHAR(255),
column2 INT,
...
);
```

Ensure that your CSV file does not include any characters that could disrupt the import process, such as commas within data fields without quotation marks. Save the file with UTF-8 encoding to avoid character issues during import.

Use the MySQL `LOAD DATA INFILE` command to import your CSV file into the table. First, ensure that the MySQL server has the proper permissions to read the file. Then, execute:
```sql
LOAD DATA INFILE '/path/to/your/file.csv'
INTO TABLE my_table
FIELDS TERMINATED BY ','
ENCLOSED BY '"'
LINES TERMINATED BY '\n'
IGNORE 1 ROWS;
```
Replace `'/path/to/your/file.csv'` with the actual path to your CSV file.

After the import, verify that the data in the MySQL table matches the data from Notion. You can use simple `SELECT` queries to review the data:
```sql
SELECT FROM my_table;
```
Check for any discrepancies or errors that might have occurred during the import process.

Conduct a thorough validation to ensure the data integrity is maintained. Check for duplicate records, null values, or any other issues. Use SQL queries to clean up and correct any problems:
```sql
DELETE FROM my_table WHERE column1 IS NULL;
-- Add more queries as needed to clean or transform data
```

Following these steps will help you successfully transfer your data from Notion to a MySQL database without relying on third-party connectors or integrations.