Updated on 2024-06-03 GMT+08:00

Functions and Operators

Operators can be used to process one or more operands and can be placed before, after, or between operands. Results are returned after the processing.

Functions encapsulate service logic to implement specific functions. A function may or may not have parameters. After a function is executed, the result is returned.

Users can modify system functions. However, after the modification, the meaning of the functions may change, which results in disorder in system control. Therefore, users are not allowed to manually modify system functions.

When the GUC parameter behavior_compat_options contains the 'enable_funcname_with_argsname' option, the projection alias displays the complete function.