Part II. The SQL Language

This part describes the use of the SQL language in PostgreSQL. We start with describing the general syntax of SQL, then explain how to create the structures to hold data, how to populate the database, and how to query it. The middle part lists the available data types and functions for use in SQL commands. The rest treats several aspects that are important for tuning a database for optimal performance.

The information in this part is arranged so that a novice user can follow it start to end to gain a full understanding of the topics without having to refer forward too many times. The chapters are intended to be self-contained, so that advanced users can read the chapters individually as they choose. The information in this part is presented in a narrative fashion in topical units. Readers looking for a complete description of a particular command should see Part VI.

Readers of this part should know how to connect to a PostgreSQL database and issue SQL commands. Readers that are unfamiliar with these issues are encouraged to read Part I first. SQL commands are typically entered using the PostgreSQL interactive terminal psql, but other programs that have similar functionality can be used as well.

Table of Contents

4. SQL Syntax
4.1. Lexical Structure
4.2. Value Expressions
4.3. Calling Functions
5. Data Definition
5.1. Table Basics
5.2. Default Values
5.3. Generated Columns
5.4. Constraints
5.5. System Columns
5.6. Modifying Tables
5.7. Privileges
5.8. Row Security Policies
5.9. Schemas
5.10. Inheritance
5.11. Table Partitioning
5.12. Foreign Data
5.13. Other Database Objects
5.14. Dependency Tracking
6. Data Manipulation
6.1. Inserting Data
6.2. Updating Data
6.3. Deleting Data
6.4. Returning Data from Modified Rows
7. Queries
7.1. Overview
7.2. Table Expressions
7.3. Select Lists
7.4. Combining Queries
7.5. Sorting Rows
7.7. VALUES Lists
7.8. WITH Queries (Common Table Expressions)
8. Data Types
8.1. Numeric Types
8.2. Monetary Types
8.3. Character Types
8.4. Binary Data Types
8.5. Date/Time Types
8.6. Boolean Type
8.7. Enumerated Types
8.8. Geometric Types
8.9. Network Address Types
8.10. Bit String Types
8.11. Text Search Types
8.12. UUID Type
8.13. XML Type
8.14. JSON Types
8.15. Arrays
8.16. Composite Types
8.17. Range Types
8.18. Domain Types
8.19. Object Identifier Types
8.20. pg_lsn Type
8.21. Pseudo-Types
9. Functions and Operators
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
9.8. 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
9.16. JSON Functions and Operators
9.17. Sequence Manipulation Functions
9.18. Conditional Expressions
9.19. Array Functions and Operators
9.20. Range Functions and Operators
9.21. Aggregate Functions
9.22. Window Functions
9.23. Subquery Expressions
9.24. Row and Array Comparisons
9.25. Set Returning Functions
9.26. System Information Functions and Operators
9.27. System Administration Functions
9.28. Trigger Functions
9.29. Event Trigger Functions
9.30. Statistics Information Functions
10. Type Conversion
10.1. Overview
10.2. Operators
10.3. Functions
10.4. Value Storage
10.5. UNION, CASE, and Related Constructs
10.6. SELECT Output Columns
11. Indexes
11.1. Introduction
11.2. Index Types
11.3. Multicolumn Indexes
11.4. Indexes and ORDER BY
11.5. Combining Multiple Indexes
11.6. Unique Indexes
11.7. Indexes on Expressions
11.8. Partial Indexes
11.9. Index-Only Scans and Covering Indexes
11.10. Operator Classes and Operator Families
11.11. Indexes and Collations
11.12. Examining Index Usage
12. Full Text Search
12.1. Introduction
12.2. Tables and Indexes
12.3. Controlling Text Search
12.4. Additional Features
12.5. Parsers
12.6. Dictionaries
12.7. Configuration Example
12.8. Testing and Debugging Text Search
12.9. Preferred Index Types for Text Search
12.10. psql Support
12.11. Limitations
13. Concurrency Control
13.1. Introduction
13.2. Transaction Isolation
13.3. Explicit Locking
13.4. Data Consistency Checks at the Application Level
13.5. Caveats
13.6. Locking and Indexes
14. Performance Tips
14.1. Using EXPLAIN
14.2. Statistics Used by the Planner
14.3. Controlling the Planner with Explicit JOIN Clauses
14.4. Populating a Database
14.5. Non-Durable Settings
15. Parallel Query
15.1. How Parallel Query Works
15.2. When Can Parallel Query Be Used?
15.3. Parallel Plans
15.4. Parallel Safety