4.2.5. Operator Invocations

4.2.5. Operator Invocations

4.2.5.运算符调用

There are three possible syntaxes for an operator invocation:

运算符调用有三种可能的语法：

 

expression operator expression (binary infix operator)

operator expression (unary prefix operator)

expression operator (unary postfix operator)

 

where the operator token follows the syntax rules of Section 4.1.3, or is one of the key words AND , OR , and NOT , or is a qualified operator name in the form:

operator可以是符合第4.1.3节语法规则的操作符，或者是and，or和not其中之一，或者是为以下格式的指定的操作符名称：

 

OPERATOR(schema.operatorname)

 

Which particular operators exist and whether they are unary or binary depends on what operators have  been defined by the system or the user. Chapter 9 describes the built-in operators.

存在哪些特定运算符，以及它们是一元运算符还是二进制运算符，取决于系统或用户定义了哪些运算符。 第9章介绍了内置运算符。