What is wrong with the following SQL query?

SELECT $*$ from customers left join purchases on $($customers$.$Id$=$purchases.customer$\_$id$)$ WHERE customers.last$\_$name $=\text{'}$G$\%\text{'}$

SELECT and WHERE should not be capitalized.

The WHERE clause should contain "like"

Nothing

You can't have a line break in SQL$.$

It should be a right join.