提取表和子查询的区别(derived table vs subqueries)

子查询，你们再熟悉不过了，例如：spa select employee_name from employee where employee_salary >翻译 (select avg(employee_salary) from employee)table 下面这也是一个子查询，没用到where语句。sed INSERT INTO math_study_group(id, name) SELEC

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