摘要：
对join与left join在什么场景中适用进行简单的说明与记录。 阅读全文
摘要：
In September 1789, the government of the United States was only a few months old. George Washington was president – the nation's first. Congress was new, too. Some of the early lawmakers came to the president with a question: Would he call for a national Thanksgiving? 1789年9月，美国政府才成立几个月。乔治·华盛顿是美国第一任总统。国会也新成立不久。有些早期的议员给总统提出了一个问题：你会主张一个全国性的感恩节吗？ 阅读全文