explain analyze
select a.order_id,a.customer_id,a.price,b.order_id,b.customer_id,b.customer_name from tbl_a a left join tbl_b b --(select t.order_id from tbl_b t where t.order_id= 'oid1')b on a.order_id = b.order_id where a.order_id = 'oid1' --b.order_id = 'oid1'

待研究 Nested Loop Left Join,Nested Loop,Hash Left Join