If select x from X x, Y y
The comma in the "from" clause is equivalent to an Inner Join or a pure Cartesian join?
In ETS
test 5 Q.62:
Consider the following JPQL:
select c from Customer c, IN(c.orders) o
What will this query return?
The correct answer is :
All Customers who have at least one Order.
Because the query is translated into
"For Sun
Java Application Server and MySQL, select c from Customer c, IN(c.orders) o actually gets translated to :
SELECT DISTINCT t0.ID, t0.LASTNAME FROM CUSTOMER t0, ORDER t1 WHERE (t1.CUSTOMER_ID = t0.ID)
"
But in
EJB in action, the book says one can perform theta join using ',' in the "from" clause.
I am totally confused.
