Chapter 9. Functions and Operators
Table of Contents
- 9.1. Logical Operators
- 9.2. Comparison Functions and Operators
- 9.3. Mathematical Functions and Operators
- 9.4. String Functions and Operators
- 9.5. Binary String Functions and Operators
- 9.6. Bit String Functions and Operators
- 9.7. Pattern Matching
- 9.2. Comparison Functions and Operators
- 9.8. Data Type Formatting Functions
- 9.9. Date/Time Functions and Operators
- 9.10. Enum Support Functions
- 9.11. Geometric Functions and Operators
- 9.12. Network Address Functions and Operators
- 9.13. Text Search Functions and Operators
- 9.14. UUID Functions
- 9.15. XML Functions
- 9.11. Geometric Functions and Operators
- 9.16. JSON Functions and Operators
- 9.17. Sequence Manipulation Functions
- 9.18. Conditional Expressions
- 9.19. Array Functions and Operators
- 9.20. Range/Multirange Functions and Operators
- 9.21. Aggregate Functions
- 9.22. Window Functions
- 9.23. Merge Support Functions
- 9.24. Subquery Expressions
- 9.20. Range/Multirange Functions and Operators
- 9.25. Row and Array Comparisons
- 9.26. Set Returning Functions
- 9.27. System Information Functions and Operators
- 9.27.1. Session Information Functions
- 9.27.2. Access Privilege Inquiry Functions
- 9.27.3. Schema Visibility Inquiry Functions
- 9.27.4. System Catalog Information Functions
- 9.27.5. Object Information and Addressing Functions
- 9.27.6. Comment Information Functions
- 9.27.7. Data Validity Checking Functions
- 9.27.8. Transaction ID and Snapshot Information Functions
- 9.27.9. Committed Transaction Information Functions
- 9.27.10. Control Data Functions
- 9.27.11. Version Information Functions
- 9.27.12. WAL Summarization Information Functions
- 9.27.2. Access Privilege Inquiry Functions
- 9.27.1. Session Information Functions
- 9.28. System Administration Functions
- 9.28.1. Configuration Settings Functions
- 9.28.2. Server Signaling Functions
- 9.28.3. Backup Control Functions
- 9.28.4. Recovery Control Functions
- 9.28.5. Snapshot Synchronization Functions
- 9.28.6. Replication Management Functions
- 9.28.7. Database Object Management Functions
- 9.28.8. Index Maintenance Functions
- 9.28.9. Generic File Access Functions
- 9.28.10. Advisory Lock Functions
- 9.28.11. Operation Log Support Functions
- 9.28.12. Debugging Functions
- 9.28.13. Troubleshooting Functions
- 9.28.2. Server Signaling Functions
- 9.28.1. Configuration Settings Functions
- 9.29. Trigger Functions
- 9.30. Event Trigger Functions
- 9.31. Statistics Information Functions
Postgres Pro provides a large number of functions and operators for the built-in data types. This chapter describes most of them, although additional special-purpose functions appear in relevant sections of the manual. Users can also define their own functions and operators, as described inPart V. Thepsql commands\df and\do can be used to list all available functions and operators, respectively.
The notation used throughout this chapter to describe the argument and result data types of a function or operator is like this:
repeat(text,integer) →text
which says that the functionrepeat takes one text and one integer argument and returns a result of type text. The right arrow is also used to indicate the result of an example, thus:
repeat('Pg', 4) →PgPgPgPgIf you are concerned about portability then note that most of the functions and operators described in this chapter, with the exception of the most trivial arithmetic and comparison operators and some explicitly marked functions, are not specified by theSQL standard. Some of this extended functionality is present in otherSQL database management systems, and in many cases this functionality is compatible and consistent between the various implementations.