Overview of operators

Operators are generally used to connect operands or parameters and return a result. In terms of syntax, operators can appear before, after, or between operands.

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

Common operators can be divided into unary and binary operators:

• Unary operators

  Unary operators operate on a single operand. The common format of a unary operator is as follows:

  operator operand
  

• Binary operators

  Binary operators operate on two operands. The common format of a binary operator is as follows:

  operand1 operator operand2
  

  Note

  • Other operators with special formats can accept more than two operands.
  • If an operator is provided with a NULL operand, the result is always NULL. The only exception is the concatenation operator (||).

This chapter focuses on non-logical (non-boolean) operators, which cannot be used as WHERE or HAVING conditions in queries or subqueries. OceanBase Database currently supports the following operators:

• Arithmetic operators

• Concatenation operators

• Hierarchical query operators

• Set operators

• COLLATE operators