An operation can be a relational operator, a system - or user-defined function, or an SQL operator, such as GROUP BY, ORDER BY, and so on.

操作可以是一个关系运算符，或者系统或用户定义的函数，也可以是一个sql操作符，例如GROUP BY、ORDER BY等。

youdao

The friendly communication interface and intelligent study function of expert system are provided, which is convenient for the experiment operator to study the knowledge and accumulate experience.

通信界面人性化，配有专家系统等智能学习功能，便于实验操作人员对实验知识的掌握和经验积累。

youdao