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2.2.5 Operator Invocations

There are three possible syntaxes for an operator invocation:

• 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 2.1.3 Operators, or is one of the key words AND, OR, and NOT, or is a qualified operator name in the form:

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. section 7 Functions and Operators describes the built-in operators.