Hi Ercole,
Why don't you create 2 joins separately? A join between 2 tables (A,B) first, another join between 2 tables (B,C)?
What's the requirement? What's the relationship between tables? What does the data look like? Some more details can help us to help you better.
Check these out:
How to join three tables in SQL query – MySQL Example
Thanks,
Mahboob Mohammed