1.一个大表和一个小表(驱动表)连接，连接方式可以是等值或者是不等值 也可能比nested loop更快,因为处理内存中的hash表比处理b-tree索引更快 ...

For Nested Loop case, which order is better ? Big to Small or Small to Big ? I think your guys should understand what is Nested Loop first. Here is a sample SQL. select * from Big,Small S*LN(B)/2 the ...