不考虑性能,查询 A 和 B 的结果会相同吗?C 和 D 呢?
----- Scenario 1:
-- A (left join)
select *
from a left join b
on <blahblah>
left join c
on <blahblan>
-- B (left join)
select *
from a left join c
on <blahblah>
left join b
on <blahblan>
----- Scenario 2:
-- C (inner join)
select *
from a join b
on <blahblah>
join c
on <blahblan>
-- D (inner join)
select *
from a join c
on <blahblah>
join b
on <blahblan>