摘要：
--SQL 版本select @@version--与表无关的数据select newid() as TGUID--聚合函数，对查询结果进行聚合求值select count(*) from select max(Salary) fromselect min(Salary) fromselect Avg(Salary) fromselect sum(salary) from --排序order by Age DESC, Salary ASC--通配符匹配(半角),模糊匹配where EmpName like '_N' or '%n%'--NULL:不知道selec 阅读全文
