PYSPARK & SQL nested list comprehension: how to select specific iterations in the for loop

Question

I have two lists that I want to use string manipulation on.

sourceTable=["customer_{KERNEL}","material_{KERNEL}"]
kernel=["a","b","c"]

My output needs to look like this:

SELECT * FROM customer_a x LEFT JOIN material_a y ON x.id=y.id
SELECT * FROM customer_b x LEFT JOIN material_b y ON x.id=y.id
SELECT * FROM customer_c x LEFT JOIN material_c y ON x.id=y.id

I have been trying to get it to work by using nested list comprehensions but I have been struggling as the order in which the items in the list appear does not work.

Can anyone help and point me in the right direction?