Overview

An operator joins individual data items such as operands or parameters and returns a result. Syntactically, an operator can appear before an operand, after an operand, or between two operands.

Operators are represented by special characters or keywords. For example, the division operator is represented by a forward slash (/).

General operators can be categorized into unary and binary operators.

• Unary operators

  A unary operator operates on only one operand. A unary operator typically appears in the following format:

  operator operand
  

• Binary operators

  As the name suggests, a binary operator operates on two operands. A binary operator typically appears in the following format:

  operand1 operator operand2
  

  Note

  • Other operators with special formats can accept more than two operands.
  • If an operator is given a NULL operand, the result is always NULL. The only operator that does not follow this rule is the concatenation operator (||).

This chapter describes non-logical (non-Boolean) operators that cannot be used alone as the WHERE or HAVING condition in queries or subqueries. OceanBase Database supports the following operators:

• Arithmetic operators

• Concatenation operator

• Hierarchical query operators

• Set operators

• COLLATE operator