Constant Expression

A constant expression is an expression that consists only of:

• Literals (fixed data values)
• Parameter markers (references to variables)
• Constant functions, such as CURRENT_TIMESTAMP.

  Example:

  • 123
  • 1 + 2
  • TIMESTAMP '2009-12-12 00:10:00'
  • OPC'D'
  • CURRENT_TIMESTAMP
  • ?
  • ? || '%'

In the various expressions and conditions used throughout the SQL Join Optimization documentation, Value1, Value2, and so on, are used to represent constant expressions.