最佳答案
假设您使用的是InnoDB,第一个问题的答案通常是肯定的,这意味着第二个问题的答案通常是否.
原文链接：https://www.f2er.com/mysql/532043.html默认情况下,MysqL的InnoDB使用一种称为consistent non-locking reads的技术：
The query sees the changes made by
transactions that committed before
that point of time,and no changes
made by later or uncommitted
transactions. The exception to this
rule is that the query sees the
changes made by earlier statements
within the same transaction.
话虽这么说,关于交易还有很多事情要知道.您可以更改isolation level of a transaction以更彻底地控制交易结果.
关于InnoDB Transaction Model的章节是一个很好的起点.