初始查询中的XMLEXISTS谓词被转换为一个复杂表达式，可以通过编号Q 1引用。

The XMLEXISTS predicate in the original query got converted into a complex expression that can be referred to using the number Q1.

youdao

本文不介绍用于动态选择Web服务的其他选项(例如确定最低执行成本或最佳质量的复杂表达式)。

Other options for dynamically selecting Web services (such as complex expressions that determine least execution cost or the best quality) are not covered here.

youdao

表达式可以简单到就是一个变量（如清单 2 所示）或者是一个方法调用（例如 getList()），亦或是包含布尔逻辑或三目运算符的复杂表达式。

This expression can be as simple as a variable (as shown in Listing 2) or a method call (like getList()), or a complex expression that involves boolean logic or a ternary operator.

youdao

Right, having done that, we can certainly get to more complicated things, so for example, suppose I look at that expression.

好，说完了这一点，我们就可以讲些复杂些的话题了，例如，假设我看到了这个表达式。

麻省理工公开课 - 计算机科学及编程导论课程节选

We can start having complex expressions, you can imagine we can have things are lots of parens, and all sorts of things in it. Yes, question.

我们可以开始写复杂点的表达式了，你可以想象,我们有一个很多括号的表达式，里面有各种各样的东西，什么问题。

麻省理工公开课 - 计算机科学及编程导论课程节选