PostgreSQL join where 条件不同 explain 执行计划的差别

explain analyzeselect a.order_id, a.customer_id, a.price,b.order_id, b.customer_id, b.customer_namefrom tbl_a aleft jointbl_b b--(select t.order_id from tbl_b t where t.order_id= 'oid1')bon a.order_id = b.order_idwhere a.order_id = 'oid1'--b.order_id = 'oid1'

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