SQL query: count for all the reviews that each customer has written

Lets say I have one table called “REVIEWS”

This table has Reviews that customers have written for various products.

I would like to be able to get a “count” for all the reviews that each customer has written, so I write:

SELECT count(*) AS counter
FROM reviews 
WHERE customers_id = 12345

Now, my problem is that I wish to have a count like above BUT only for customers who have written a SPECIFIC product review

For instance,

SELECT customers_review
FROM reviews
WHERE
products_id = '170' 

In summary, I wish to be able to get the customers TOTAL COUNT for every review they have written, but ONLY for customers who have written a review for a specific product.

Answer

select customers_id, count(*)
from reviews
where customers_id in 
(select customers_id from reviews where products_id = '170')
group by customers_id;