PostgreSQL 正體中文使用手冊
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  • 簡介
  • 前言
    • 1. 什麼是PostgreSQL?
    • 2. PostgreSQL沿革
    • 3. 慣例
    • 4. 其他參考資訊
    • 5. 問題回報指南
  • I. 新手教學
    • 1. 入門指南
      • 1.1. 安裝
      • 1.2. 基礎架構
      • 1.3. 建立一個資料庫
      • 1.4. 存取一個資料庫
    • 2. SQL查詢語言
      • 2.1. 簡介
      • 2.2. 概念
      • 2.3. 創建一個新的資料表
      • 2.4. 資料列是資料表的組成單位
      • 2.5. 資料表的查詢
      • 2.6. 交叉查詢
      • 2.7. 彙總查詢
      • 2.8. 更新資料
      • 2.9. 刪除資料
    • 3. 先進功能
      • 3.1. 簡介
      • 3.2. 檢視表(View)
      • 3.3. 外部索引鍵
      • 3.4. 交易安全
      • 3.5. 窗函數
      • 3.6. 繼承
      • 3.7. 結論
  • II. SQL查詢語言
    • 4. SQL語法
      • 4.1. 語法結構
      • 4.2. 參數表示式
      • 4.3. 函數呼叫
    • 5. 定義資料結構
      • 5.1. 認識資料表
      • 5.2. 預設值
      • 5.3. 限制條件
      • 5.4. 系統欄位
      • 5.5. 表格變更
      • 5.6. 權限
      • 5.7. 資料列安全原則
      • 5.8. Schemas
      • 5.9. 繼承
      • 5.10. 分割資料表
      • 5.11. 外部資料
      • 5.12. 其他資料庫物件
      • 5.13. 相依性追蹤
    • 6. 資料處理
      • 6.1. 新增資料
      • 6.2. 更新資料
      • 6.3. 刪除資料
      • 6.4. 修改並回傳資料
    • 7. 資料查詢
      • 7.1. 概觀
      • 7.2. 資料表表示式
      • 7.3. 取得資料列表
      • 7.4. 合併查詢結果
      • 7.5. 資料排序
      • 7.6. 指定資料範圍
      • 7.7. 列舉資料
      • 7.8. 遞迴查詢(Common Table Expressions)
    • 8. 資料型別
      • 8.1. 數字型別
      • 8.2. 貨幣型別
      • 8.3. 字串型別
      • 8.4. 位元組型別(bytea)
      • 8.5. 日期時間型別
      • 8.6. 布林型別
      • 8.7. 列舉型別
      • 8.8. 地理資訊型別
      • 8.9. 網路資訊型別
      • 8.10. 位元字串型別
      • 8.11. 全文檢索型別
      • 8.12. UUID型別
      • 8.13. XML型別
      • 8.14. JSON型別
      • 8.15. 陣列
      • 8.16. 複合型別
      • 8.17. 範圍型別
      • 8.18. 指標型別
      • 8.19. pg_lsn型別
      • 8.20. 概念型別
    • 9. 函式及運算子
      • 9.1. 邏輯運算子
      • 9.2. 比較函式及運算子
      • 9.3. 數學函式及運算子
      • 9.4. 字串函式及運算子
      • 9.5. 位元字串函式及運算子
      • 9.6. 二元字串函式及運算子
      • 9.7. 特徵比對
      • 9.8. 型別轉換函式
      • 9.9 日期時間函式及運算子
      • 9.10. 列舉型別函式
      • 9.11. 地理資訊函式及運算子
      • 9.12. 網路位址函式及運算子
      • 9.13. 文字檢索函式及運算子
      • 9.14. XML函式
      • 9.15. JSON函式及運算子
      • 9.16. 序列函式
      • 9.17. 條件表示式
      • 9.18. 陣列函式及運算子
      • 9.19. 範圍函式及運算子
      • 9.20. 彙總函數
      • 9.21. Window函式
      • 9.22. 子查詢
      • 9.23. 資料列與陣列的比較運算
      • 9.24. 集合回傳函式
      • 9.25. 系統資訊函數
      • 9.26. 系統管理函式
      • 9.27. 觸發函式
      • 9.28. 事件觸發函式
    • 10. 型別轉換
      • 10.1. 概觀
      • 10.2. 運算子
      • 10.3. 函式
      • 10.4. 資料儲存轉換規則
      • 10.5. UNION、CASE 等相關結構
      • 10.6. SELECT輸出規則
    • 11. 索引(Index)
      • 11.1. 簡介
      • 11.2. 索引型別
      • 11.3. 多欄位索引
      • 11.4. 索引與ORDER BY
      • 11.5. 善用多個索引
      • 11.6. 唯一值索引
      • 11.7. 表示式索引
      • 11.8. 部份索引(partial index)
      • 11.9. 運算子物件及家族
      • 11.10. 索引與排序規則
      • 11.11. 索引限定查詢(Index-only scan)
      • 11.12. 檢查索引運用
    • 12. 全文檢索
      • 12.1. 簡介
      • 12.2. 查詢與索引
      • 12.3. 細部控制
      • 12.4. 延伸功能
      • 12.5. 斷詞
      • 12.6. 字典
      • 12.7. 組態範例
      • 12.8. 測試與除錯
      • 12.9. GIN及GiST索引型別
      • 12.10. psql支援
      • 12.11. 功能限制
    • 13. 一致性管理(MVCC)
      • 13.1. 簡介
      • 13.2. 交易隔離
      • 13.3. 鎖定模式
      • 13.4. 在應用端檢視資料一致性
      • 13.5. 特別注意
      • 13.6. 鎖定與索引
    • 14. 效能技巧
      • 14.1. 善用EXPLAIN
      • 14.2. 統計資訊
      • 14.3. 使用確切的JOIN方式
      • 14.4. 快速建立資料庫內容
      • 14.5. 彈性設定
    • 15. 平行查詢
      • 15.1. 如何運作?
      • 15.2. 啓用時機?
      • 15.3. 平行查詢計畫
      • 15.4. 平行查詢的安全性
  • III. 系統管理
    • 16. 用原始碼安裝
      • 16.1. Short Version
      • 16.2. Requirements
      • 16.3. Getting The Source
      • 16.4. 安裝流程
      • 16.5. Post-Installation Setup
      • 16.6. Supported Platforms
      • 16.7. 平台相關的注意事項
    • 17. 用原始碼在 Windows 上安裝
      • 17.1. Building with Visual C++ or the Microsoft Windows SDK
    • 18. 服務配置與維運
      • 18.1. PostgreSQL 使用者帳號
      • 18.2. Creating a Database Cluster
      • 18.3. Starting the Database Server
      • 18.4. 核心資源管理
      • 18.5. Shutting Down the Server
      • 18.6. Upgrading a PostgreSQL Cluster
      • 18.7. Preventing Server Spoofing
      • 18.8. Encryption Options
      • 18.9. Secure TCP/IP Connections with SSL
      • 18.10. Secure TCP/IP Connections with SSH Tunnels
      • 18.11. 在 Windows 註冊事件日誌
    • 19. 服務組態設定
      • 19.1. Setting Parameters
      • 19.2. File Locations
      • 19.3. 連線與認證
      • 19.4. 資源配置
      • 19.5. Write Ahead Log
      • 19.6. 複寫(Replication)
      • 19.7. 查詢規畫
      • 19.8. 錯誤回報與日誌記錄
      • 19.9. Run-time Statistics
      • 19.10. 自動資料庫清理
      • 19.11. 用戶端連線預設參數
      • 19.12. 交易鎖定管理
      • 19.13. 版本與平台的相容性
      • 19.14. Error Handling
      • 19.15. 預先配置的參數
      • 19.16. Customized Options
      • 19.17. Developer Options
      • 19.18. Short Options
    • 20. 使用者認證
      • 20.1. 設定檔:pg_hba.conf
      • 20.2. User Name Maps
      • 20.3. Authentication Methods
      • 20.4. Authentication Problems
    • 21. 資料庫角色
      • 21.1. Database Roles
      • 21.2. Role Attributes
      • 21.3. Role Membership
      • 21.4. 移除角色
      • 21.5. Default Roles
      • 21.6. Function Security
    • 22. Managing Databases
      • 22.1. Overview
      • 22.2. Creating a Database
      • 22.3. 樣版資料庫
      • 22.4. Database Configuration
      • 22.5. Destroying a Database
      • 22.6. Tablespaces
    • 23. 語系
      • 23.1. 語系支援
      • 23.2. Collation Support
      • 23.3. 字元集支援
    • 24. 例行性資料庫維護工作
      • 24.1. 例行性資料清理
      • 24.2. 定期重建索引
      • 24.3. Log File Maintenance
    • 25. 備份及還原
      • 25.1. SQL Dump
      • 25.2. File System Level Backup
      • 25.3. Continuous Archiving and Point-in-Time Recovery (PITR)
    • 26. High Availability, Load Balancing, and Replication
      • 26.1. Comparison of Different Solutions
      • 26.2. 日誌轉送備用伺服器 Log-Shipping Standby Servers
      • 26.3. Failover
      • 26.4. Alternative Method for Log Shipping
      • 26.5. Hot Standby
    • 27. Recovery Configuration
      • 27.1. Archive Recovery Settings
      • 27.2. Recovery Target Settings
      • 27.3. Standby Server Settings
    • 28. 監控資料庫活動
      • 28.1. Standard Unix Tools
      • 28.2. 統計資訊收集器
      • 28.3. Viewing Locks
      • 28.4. Progress Reporting
      • 28.5. Dynamic Tracing
    • 29. Monitoring Disk Usage
      • 29.1. Determining Disk Usage
      • 29.2. Disk Full Failure
    • 30. 高可靠度及預寫日誌
      • 30.1. Reliability
      • 30.2. Write-Ahead Logging (WAL)
      • 30.3. Asynchronous Commit
      • 30.4. WAL Configuration
      • 30.5. WAL Internals
    • 31. 邏輯複寫(Logical Replication)
      • 31.1. 發佈(Publication)
      • 31.2. 訂閱(Subscription)
      • 31.3. 衝突處理
      • 31.4. 限制
      • 31.5. 架構
      • 31.6. 監控
      • 31.7. 安全性
      • 31.8. 系統設定
      • 31.9. 快速設定
    • 32. Just-in-Time Compilation (JIT)
      • 32.1. What is JIT compilation?
      • 32.2. When to JIT?
      • 32.3. Configuration
      • 32.4. Extensibility
    • 33. 迴歸測試
      • 33.1. Running the Tests
      • 33.2. Test Evaluation
      • 33.3. Variant Comparison Files
      • 33.4. TAP Tests
      • 33.5. Test Coverage Examination
  • IV. 用戶端介面
    • 34. libpq - C Library
      • 34.1. 資料庫連線控制函數
      • 34.2. 連線狀態函數
      • 34.3. Command Execution Functions
      • 34.4. Asynchronous Command Processing
      • 34.5. Retrieving Query Results Row-By-Row
      • 34.6. Canceling Queries in Progress
      • 34.7. The Fast-Path Interface
      • 34.8. Asynchronous Notification
      • 34.9. Functions Associated with the COPY Command
      • 34.10. Control Functions
      • 34.11. Miscellaneous Functions
      • 34.12. Notice Processing
      • 34.13. Event System
      • 34.14. 環境變數
      • 34.15. 密碼檔
      • 34.16. The Connection Service File
      • 34.17. LDAP Lookup of Connection Parameters
      • 34.18. SSL Support
      • 34.19. Behavior in Threaded Programs
      • 34.20. Building libpq Programs
      • 34.21. Example Programs
    • 35. Large Objects
      • 35.1. Introduction
      • 35.2. Implementation Features
      • 35.3. Client Interfaces
      • 35.4. Server-side Functions
      • 35.5. Example Program
    • 36. ECPG - Embedded SQL in C
      • 36.1. The Concept
      • 36.2. Managing Database Connections
      • 36.3. Running SQL Commands
      • 36.4. Using Host Variables
      • 36.5. Dynamic SQL
      • 36.6. pgtypes Library
      • 36.7. Using Descriptor Areas
      • 36.8. Error Handling
      • 36.9. Preprocessor Directives
      • 36.10. Processing Embedded SQL Programs
      • 36.11. Library Functions
      • 36.12. Large Objects
      • 36.13. C++ Applications
      • 36.14. Embedded SQL Commands
      • 36.15. Informix Compatibility Mode
      • 36.16. Internals
    • 37. The Information Schema
      • 37.1. The Schema
      • 37.2. Data Types
      • 37.3. information_schema_catalog_name
      • 37.4. administrable_role_authorizations
      • 37.5. applicable_roles
      • 37.6. attributes
      • 37.7. character_sets
      • 37.8. check_constraint_routine_usage
      • 37.9. check_constraints
      • 37.10. collations
      • 37.11. collation_character_set_applicability
      • 37.12. column_domain_usage
      • 37.13. column_options
      • 37.14. column_privileges
      • 37.15. column_udt_usage
      • 37.16. columns
      • 37.17. constraint_column_usage
      • 37.18. constraint_table_usage
      • 37.19. data_type_privileges
      • 37.20. domain_constraints
      • 37.21. domain_udt_usage
      • 37.22. domains
      • 37.23. element_types
      • 37.24. enabled_roles
      • 37.25. foreign_data_wrapper_options
      • 37.26. foreign_data_wrappers
      • 37.27. foreign_server_options
      • 37.28. foreign_servers
      • 37.29. foreign_table_options
      • 37.30. foreign_tables
      • 37.31. key_column_usage
      • 37.32. parameters
      • 37.33. referential_constraints
      • 37.34. role_column_grants
      • 37.35. role_routine_grants
      • 37.36. role_table_grants
      • 37.37. role_udt_grants
      • 37.38. role_usage_grants
      • 37.39. routine_privileges
      • 37.40. routines
      • 37.41. schemata
      • 37.42. sequences
      • 37.43. sql_features
      • 37.44. sql_implementation_info
      • 37.45. sql_languages
      • 37.46. sql_packages
      • 37.47. sql_parts
      • 37.48. sql_sizing
      • 37.49. sql_sizing_profiles
      • 37.50. table_constraints
      • 37.51. table_privileges
      • 37.52. tables
      • 37.53. transforms
      • 37.54. triggered_update_columns
      • 37.55. triggers
      • 37.56. udt_privileges
      • 37.57. usage_privileges
      • 37.58. user_defined_types
      • 37.59. user_mapping_options
      • 37.60. user_mappings
      • 37.61. view_column_usage
      • 37.62. view_routine_usage
      • 37.63. view_table_usage
      • 37.64. views
  • V. 資料庫程式設計
    • 38. SQL 延伸功能
      • 38.1. How Extensibility Works
      • 38.2. The PostgreSQL Type System
      • 38.3. 使用者自訂函數
      • 38.4. User-defined Procedures
      • 38.5. Query Language (SQL) Functions
      • 38.6. Function Overloading
      • 38.7. 函數易變性類別
      • 38.8. Procedural Language Functions
      • 38.9. Internal Functions
      • 38.10. C-Language Functions
      • 38.11. User-defined Aggregates
      • 38.12. User-defined Types
      • 38.13. User-defined Operators
      • 38.14. Operator Optimization Information
      • 38.15. Interfacing Extensions To Indexes
      • 38.16. Packaging Related Objects into an Extension
      • 38.17. Extension Building Infrastructure
    • 39. Triggers
    • 40. Event Triggers
    • 41. 規則系統
      • 41.1. The Query Tree
      • 41.2. Views and the Rule System
      • 41.3. Materialized Views
      • 41.4. Rules on INSERT, UPDATE, and DELETE
      • 41.5. 規則及權限
      • 41.6. Rules and Command Status
      • 41.7. Rules Versus Triggers
    • 42. Procedural Languages(程序語言)
      • 42.1. Installing Procedural Languages
    • 43. PL/pgSQL - SQL Procedural Language
      • 43.5. 基本語法
    • 44. PL/Tcl - Tcl Procedural Language
    • 45. PL/Perl - Perl Procedural Language
    • 46. PL/Python - Python Procedural Language
    • 47. Server Programming Interface
    • 48. Background Worker Processes
    • 49. Logical Decoding
    • 50. Replication Progress Tracking
  • VI. 參考資訊
    • I. SQL 指令
      • ALTER DATABASE
      • ALTER DEFAULT PRIVILEGES
      • ALTER EXTENSION
      • ALTER FUNCTION
      • ALTER INDEX
      • ALTER LANGUAGE
      • ALTER MATERIALIZED VIEW
      • ALTER POLICY
      • ALTER PUBLICATION
      • ALTER ROLE
      • ALTER RULE
      • ALTER SCHEMA
      • ALTER SEQUENCE
      • ALTER STATISTICS
      • ALTER SUBSCRIPTION
      • ALTER TABLE
      • ALTER TABLESPACE
      • ALTER TRIGGER
      • ALTER TYPE
      • ALTER VIEW
      • ANALYZE
      • CLUSTER
      • COMMENT
      • COPY
      • CREATE CAST
      • CREATE DATABASE
      • CREATE EXTENSION
      • CREATE FOREIGN TABLE
      • CREATE FOREIGN DATA WRAPPER
      • CREATE FUNCTION
      • CREATE INDEX
      • CREATE LANGUAGE
      • CREATE MATERIALIZED VIEW
      • CREATE DOMAIN
      • CREATE POLICY
      • CREATE PROCEDURE
      • CREATE PUBLICATION
      • CREATE ROLE
      • CREATE RULE
      • CREATE SCHEMA
      • CREATE SEQUENCE
      • CREATE SERVER
      • CREATE STATISTICS
      • CREATE SUBSCRIPTION
      • CREATE TABLE
      • CREATE TABLE AS
      • CREATE TABLESPACE
      • CREATE TRANSFORM
      • CREATE TRIGGER
      • CREATE TYPE
      • CREATE USER
      • CREATE USER MAPPING
      • CREATE VIEW
      • DELETE
      • DO
      • DROP DATABASE
      • DROP EXTENSION
      • DROP FUNCTION
      • DROP INDEX
      • DROP LANGUAGE
      • DROP MATERIALIZED VIEW
      • DROP OWNED
      • DROP POLICY
      • DROP ROLE
      • DROP RULE
      • DROP SCHEMA
      • DROP SEQUENCE
      • DROP STATISTICS
      • DROP SUBSCRIPTION
      • DROP TABLE
      • DROP TABLESPACE
      • DROP TRANSFORM
      • DROP TRIGGER
      • DROP TYPE
      • DROP USER
      • DROP VIEW
      • EXECUTE
      • EXPLAIN
      • GRANT
      • IMPORT FOREIGN SCHEMA
      • INSERT
      • LISTEN
      • LOAD
      • NOTIFY
      • PREPARE TRANSACTION
      • REASSIGN OWNED
      • REFRESH MATERIALIZED VIEW
      • REINDEX
      • RESET
      • REVOKE
      • SELECT
      • SELECT INTO
      • SET
      • SET CONSTRAINTS
      • SET ROLE
      • SET SESSION AUTHORIZATION
      • SET TRANSACTION
      • SHOW
      • TRUNCATE
      • UNLISTEN
      • UPDATE
      • VACUUM
      • VALUES
    • II. PostgreSQL 用戶端工具
      • createdb
      • createuser
      • dropdb
      • dropuser
      • pgbench
      • pg_dump
      • psql
      • vacuumdb
    • III. PostgreSQL 伺服器應用程式
      • pg_test_timing
      • postgres
  • VII. 資料庫進階
    • 52. 系統目錄
      • 52.3. pg_am
      • 52.7. pg_attribute
      • 52.8. pg_authid
      • 52.9. pg_auth_members
      • 52.11 pg_class
      • 52.12. pg_collation
      • 52.13. pg_constraint
      • 52.15 pg_database
      • 52.26 pg_index
      • 52.29. pg_language
      • 52.32. pg_namespace
      • 52.33. pg_opclass
      • 52.38. pg_policy
      • 52.39. pg_proc
      • 52.44. pg_rewrite
      • 52.50. pg_statistic
      • 52.51. pg_statistic_ext
      • 52.54. pg_tablespace
      • 52.56. pg_trigger
      • 52.62. pg_type
      • 52.79. pg_replication_origin_status
      • 52.81 pg_roles
      • 52.85. pg_settings
      • 52.87. pg_stats
    • 53. Frontend/Backend Protocol
      • 53.1. Overview
      • 53.2. Message Flow
      • 53.3. SASL Authentication
      • 53.4. Streaming Replication Protocol
      • 53.5. Logical Streaming Replication Protocol
      • 53.6. Message Data Types
      • 53.7. Message Formats
      • 53.8. Error and Notice Message Fields
      • 53.9. Logical Replication Message Formats
      • 53.10. Summary of Changes since Protocol 2.0
    • 54. PostgreSQL 程式撰寫慣例
      • 54.1. Formatting
      • 54.2. Reporting Errors Within the Server
      • 54.3. Error Message Style Guide
      • 54.4. Miscellaneous Coding Conventions
    • 56. Writing A Procedural Language Handler
    • 64. GiST Indexes
      • 64.1. Introduction
      • 64.2. Built-in Operator Classes
      • 64.3. Extensibility
      • 64.4. Implementation
      • 64.5. Examples
    • 65. SP-GiST Indexes
      • 65.1. Introduction
      • 65.2. Built-in Operator Classes
      • 65.3. Extensibility
      • 65.4. Implementation
      • 65.5. Examples
    • 66. GIN 索引
      • 66.1. 簡介
      • 66.2. 內建運算子類
      • 66.3. Extensibility
      • 66.4. Implementation
      • 66.5. GIN Tips and Tricks
      • 66.6. Limitations
      • 66.7. Examples
    • 67. BRIN Indexes
      • 67.1. Introduction
      • 67.2. Built-in Operator Classes
      • 67.3. Extensibility
    • 68. 資料庫實體儲存格式
      • 68.2. TOAST
      • 68.4 可視性映射表(Visibility Map)
    • 70. How the Planner Uses Statistics
      • 70.2. Multivariate Statistics Examples
  • VIII. 附錄
    • A. PostgreSQL錯誤代碼
    • B. 日期時間格式支援
      • B.1. 日期時間解譯流程
      • B.2. 日期時間慣用字
      • B.3. 日期時間設定檔
      • B.4. 日期時間的沿革
    • C. SQL 關鍵字
    • D. SQL 相容性
    • E. 版本資訊
    • F. 延伸支援模組
      • F.4. auto_explain
      • F.11. dblink
        • dblink
      • F.33. pg_visibility
    • G. Additional Supplied Programs
      • G.1. Client Applications
        • oid2name
        • vacuumlo
      • G.2. Server Applications
        • pg_standby
    • H. 外部專案
      • H.1. 用戶端介面
      • H.2. Administration Tools
      • H.3. Procedural Languages
      • H.4. Extensions
    • I. The Source Code Repository
      • I.1. Getting The Source via Git
    • J. 文件取得
    • K. 縮寫字
  • 參考書目
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  1. II. SQL查詢語言
  2. 9. 函式及運算子

9.15. JSON函式及運算子

Previous9.14. XML函式Next9.16. 序列函式

Last updated 7 years ago

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shows the operators that are available for use with the two JSON data types (see).

Table 9.43. jsonandjsonbOperators

Operator

Right Operand Type

Description

Example

Example Result

->

int

Get JSON array element (indexed from zero, negative integers count from the end)

'[{"a":"foo"},{"b":"bar"},{"c":"baz"}]'::json->2

{"c":"baz"}

->

text

Get JSON object field by key

'{"a": {"b":"foo"}}'::json->'a'

{"b":"foo"}

->>

int

Get JSON array element astext

'[1,2,3]'::json->>2

3

->>

text

Get JSON object field astext

'{"a":1,"b":2}'::json->>'b'

2

#>

text[]

Get JSON object at specified path

'{"a": {"b":{"c": "foo"}}}'::json#>'{a,b}'

{"c": "foo"}

#>>

text[]

Get JSON object at specified path astext

'{"a":[1,2,3],"b":[4,5,6]}'::json#>>'{a,2}'

3

Note

There are parallel variants of these operators for both thejsonandjsonbtypes. The field/element/path extraction operators return the same type as their left-hand input (eitherjsonorjsonb), except for those specified as returningtext, which coerce the value to text. The field/element/path extraction operators return NULL, rather than failing, if the JSON input does not have the right structure to match the request; for example if no such element exists. The field/element/path extraction operators that accept integer JSON array subscripts all support negative subscripting from the end of arrays.

The standard comparison operators shown inare available forjsonb, but not forjson. They follow the ordering rules for B-tree operations outlined at.

Some further operators also exist only forjsonb, as shown in. Many of these operators can be indexed byjsonboperator classes. For a full description ofjsonbcontainment and existence semantics, see.describes how these operators can be used to effectively indexjsonbdata.

Table 9.44. AdditionaljsonbOperators

Operator

Right Operand Type

Description

Example

@>

jsonb

Does the left JSON value contain the right JSON path/value entries at the top level?

'{"a":1, "b":2}'::jsonb @> '{"b":2}'::jsonb

<@

jsonb

Are the left JSON path/value entries contained at the top level within the right JSON value?

'{"b":2}'::jsonb <@ '{"a":1, "b":2}'::jsonb

?

text

Does the_string_exist as a top-level key within the JSON value?

'{"a":1, "b":2}'::jsonb ? 'b'

`?

`

text[]

Do any of these array_strings_exist as top-level keys?

`'{"a":1, "b":2, "c":3}'::jsonb ?

array['b', 'c']`

?&

text[]

Do all of these array_strings_exist as top-level keys?

'["a", "b"]'::jsonb ?& array['a', 'b']

`

`

jsonb

Concatenate twojsonbvalues into a newjsonbvalue

`'["a", "b"]'::jsonb

'["c", "d"]'::jsonb`

-

text

Delete key/value pair or_string_element from left operand. Key/value pairs are matched based on their key value.

'{"a": "b"}'::jsonb - 'a'

-

text[]

Delete multiple key/value pairs or_string_elements from left operand. Key/value pairs are matched based on their key value.

'{"a": "b", "c": "d"}'::jsonb - '{a,c}'::text[]

-

integer

Delete the array element with specified index (Negative integers count from the end). Throws an error if top level container is not an array.

'["a", "b"]'::jsonb - 1

#-

text[]

Delete the field or element with specified path (for JSON arrays, negative integers count from the end)

'["a", {"b":1}]'::jsonb #- '{1,b}'

Note

The||operator concatenates the elements at the top level of each of its operands. It does not operate recursively. For example, if both operands are objects with a common key field name, the value of the field in the result will just be the value from the right hand operand.

Table 9.45. JSON Creation Functions

Function

Description

Example

Example Result

to_json(anyelement)to_jsonb(anyelement)

Returns the value asjsonorjsonb. Arrays and composites are converted (recursively) to arrays and objects; otherwise, if there is a cast from the type tojson, the cast function will be used to perform the conversion; otherwise, a scalar value is produced. For any scalar type other than a number, a Boolean, or a null value, the text representation will be used, in such a fashion that it is a validjsonorjsonbvalue.

to_json('Fred said "Hi."'::text)

"Fred said \"Hi.\""

array_to_json(anyarray [, pretty_bool])

Returns the array as a JSON array. A PostgreSQL multidimensional array becomes a JSON array of arrays. Line feeds will be added between dimension-1 elements if_pretty_bool_is true.

array_to_json('{ {1,5},{99,100} }'::int[])

[[1,5],[99,100]]

row_to_json(record [, pretty_bool])

Returns the row as a JSON object. Line feeds will be added between level-1 elements if_pretty_bool_is true.

row_to_json(row(1,'foo'))

{"f1":1,"f2":"foo"}

json_build_array(VARIADIC "any")jsonb_build_array(VARIADIC "any")

Builds a possibly-heterogeneously-typed JSON array out of a variadic argument list.

json_build_array(1,2,'3',4,5)

[1, 2, "3", 4, 5]

json_build_object(VARIADIC "any")jsonb_build_object(VARIADIC "any")

Builds a JSON object out of a variadic argument list. By convention, the argument list consists of alternating keys and values.

json_build_object('foo',1,'bar',2)

{"foo": 1, "bar": 2}

json_object(text[])jsonb_object(text[])

Builds a JSON object out of a text array. The array must have either exactly one dimension with an even number of members, in which case they are taken as alternating key/value pairs, or two dimensions such that each inner array has exactly two elements, which are taken as a key/value pair.

json_object('{a, 1, b, "def", c, 3.5}')json_object('{ {a, 1},{b, "def"},{c, 3.5} }')

{"a": "1", "b": "def", "c": "3.5"}

json_object(keys text[], values text[])jsonb_object(keys text[], values text[])

This form ofjson_objecttakes keys and values pairwise from two separate arrays. In all other respects it is identical to the one-argument form.

json_object('{a, b}', '{1,2}')

{"a": "1", "b": "2"}

Note

array_to_jsonandrow_to_jsonhave the same behavior asto_jsonexcept for offering a pretty-printing option. The behavior described forto_jsonlikewise applies to each individual value converted by the other JSON creation functions.

Note

Table 9.46. JSON Processing Functions

Function

Return Type

Description

Example

Example Result

json_array_length(json)jsonb_array_length(jsonb)

int

Returns the number of elements in the outermost JSON array.

json_array_length('[1,2,3,{"f1":1,"f2":[5,6]},4]')

5

json_each(json)jsonb_each(jsonb)

setof key text, value jsonsetof key text, value jsonb

Expands the outermost JSON object into a set of key/value pairs.

select * from json_each('{"a":"foo", "b":"bar"}')

key | value-----+------- a | "foo" b | "bar"

json_each_text(json)jsonb_each_text(jsonb)

setof key text, value text

Expands the outermost JSON object into a set of key/value pairs. The returned values will be of typetext.

select * from json_each_text('{"a":"foo", "b":"bar"}')

key | value-----+------- a | foo b | bar

json_extract_path(from_json json, VARIADIC path_elems text[])jsonb_extract_path(from_json jsonb, VARIADIC path_elems text[])

jsonjsonb

Returns JSON value pointed to bypath_elems(equivalent to#>operator).

json_extract_path('{"f2":{"f3":1},"f4":{"f5":99,"f6":"foo"}}','f4')

{"f5":99,"f6":"foo"}

json_extract_path_text(from_json json, VARIADIC path_elems text[])jsonb_extract_path_text(from_json jsonb, VARIADIC path_elems text[])

text

Returns JSON value pointed to by_path_elems_astext(equivalent to#>>operator).

json_extract_path_text('{"f2":{"f3":1},"f4":{"f5":99,"f6":"foo"}}','f4', 'f6')

foo

json_object_keys(json)jsonb_object_keys(jsonb)

setof text

Returns set of keys in the outermost JSON object.

json_object_keys('{"f1":"abc","f2":{"f3":"a", "f4":"b"}}')

json_object_keys------------------ f1 f2

json_populate_record(base anyelement, from_json json)jsonb_populate_record(base anyelement, from_json jsonb)

anyelement

Expands the object infrom_json_to a row whose columns match the record type defined bybase_(see note below).

select * from json_populate_record(null::myrowtype, '{"a": 1, "b": ["2", "a b"], "c": {"d": 4, "e": "a b c"}}')

a | b | c---+-----------+------------- 1 | {2,"a b"} | (4,"a b c")

json_populate_recordset(base anyelement, from_json json)jsonb_populate_recordset(base anyelement, from_json jsonb)

setof anyelement

Expands the outermost array of objects infrom_json_to a set of rows whose columns match the record type defined bybase_(see note below).

select * from json_populate_recordset(null::myrowtype, '[{"a":1,"b":2},{"a":3,"b":4}]')

a | b---+--- 1 | 2 3 | 4

json_array_elements(json)jsonb_array_elements(jsonb)

setof jsonsetof jsonb

Expands a JSON array to a set of JSON values.

select * from json_array_elements('[1,true, [2,false]]')

value----------- 1 true [2,false]

json_array_elements_text(json)jsonb_array_elements_text(jsonb)

setof text

Expands a JSON array to a set oftextvalues.

select * from json_array_elements_text('["foo", "bar"]')

value----------- foo bar

json_typeof(json)jsonb_typeof(jsonb)

text

Returns the type of the outermost JSON value as a text string. Possible types areobject,array,string,number,boolean, andnull.

json_typeof('-123.4')

number

json_to_record(json)jsonb_to_record(jsonb)

record

Builds an arbitrary record from a JSON object (see note below). As with all functions returningrecord, the caller must explicitly define the structure of the record with anASclause.

select * from json_to_record('{"a":1,"b":[1,2,3],"c":[1,2,3],"e":"bar","r": {"a": 123, "b": "a b c"}}') as x(a int, b text, c int[], d text, r myrowtype)

a | b | c | d | r---+---------+---------+---+--------------- 1 | [1,2,3] | {1,2,3} | | (123,"a b c")

json_to_recordset(json)jsonb_to_recordset(jsonb)

setof record

Builds an arbitrary set of records from a JSON array of objects (see note below). As with all functions returningrecord, the caller must explicitly define the structure of the record with anASclause.

select * from json_to_recordset('[{"a":1,"b":"foo"},{"a":"2","c":"bar"}]') as x(a int, b text);

a | b---+----- 1 | foo 2 |

json_strip_nulls(from_json json)jsonb_strip_nulls(from_json jsonb)

jsonjsonb

Returns_from_json_with all object fields that have null values omitted. Other null values are untouched.

json_strip_nulls('[{"f1":1,"f2":null},2,null,3]')

[{"f1":1},2,null,3]

jsonb_set(target jsonb, path text[], new_value jsonb[,create_missingboolean])

jsonb

Returnstarget_with the section designated bypathreplaced bynew_value, or withnew_valueadded ifcreate_missingis true ( default istrue) and the item designated bypathdoes not exist. As with the path orientated operators, negative integers that appear inpath_count from the end of JSON arrays.

jsonb_set('[{"f1":1,"f2":null},2,null,3]', '{0,f1}','[2,3,4]', false)jsonb_set('[{"f1":1,"f2":null},2]', '{0,f3}','[2,3,4]')

[{"f1":[2,3,4],"f2":null},2,null,3][{"f1": 1, "f2": null, "f3": [2, 3, 4]}, 2]

jsonb_insert(target jsonb, path text[], new_value jsonb, [insert_afterboolean])

jsonb

Returnstarget_withnew_valueinserted. Iftargetsection designated bypathis in a JSONB array,new_valuewill be inserted before target or after ifinsert_afteris true (default isfalse). Iftargetsection designated bypathis in JSONB object,new_valuewill be inserted only iftargetdoes not exist. As with the path orientated operators, negative integers that appear inpath_count from the end of JSON arrays.

jsonb_insert('{"a": [0,1,2]}', '{a, 1}', '"new_value"')jsonb_insert('{"a": [0,1,2]}', '{a, 1}', '"new_value"', true)

{"a": [0, "new_value", 1, 2]}{"a": [0, 1, "new_value", 2]}

jsonb_pretty(from_json jsonb)

text

Returns_from_json_as indented JSON text.

jsonb_pretty('[{"f1":1,"f2":null},2,null,3]')

[ { "f1": 1, "f2": null }, 2, null, 3]

Note

Note

Injson_populate_record,json_populate_recordset,json_to_recordandjson_to_recordset, type coercion from the JSON is“best effort”and may not result in desired values for some types. JSON keys are matched to identical column names in the target row type. JSON fields that do not appear in the target row type will be omitted from the output, and target columns that do not match any JSON field will simply be NULL.

Note

All the items of thepathparameter ofjsonb_setas well asjsonb_insertexcept the last item must be present in thetarget. Ifcreate_missingis false, all items of thepathparameter ofjsonb_setmust be present. If these conditions are not met thetargetis returned unchanged.

If the last path item is an object key, it will be created if it is absent and given the new value. If the last path item is an array index, if it is positive the item to set is found by counting from the left, and if negative by counting from the right --1designates the rightmost element, and so on. If the item is out of the range -array_length .. array_length -1, and create_missing is true, the new value is added at the beginning of the array if the item is negative, and at the end of the array if it is positive.

Note

Thejson_typeoffunction'snullreturn value should not be confused with a SQL NULL. While callingjson_typeof('null'::json)will returnnull, callingjson_typeof(NULL::json)will return a SQL NULL.

Note

If the argument tojson_strip_nullscontains duplicate field names in any object, the result could be semantically somewhat different, depending on the order in which they occur. This is not an issue forjsonb_strip_nullssincejsonbvalues never have duplicate object field names.

shows the functions that are available for creatingjsonandjsonbvalues. (There are no equivalent functions forjsonb, of therow_to_jsonandarray_to_jsonfunctions. However, theto_jsonbfunction supplies much the same functionality as these functions would.)

Theextension has a cast fromhstoretojson, so thathstorevalues converted via the JSON creation functions will be represented as JSON objects, not as primitive string values.

shows the functions that are available for processingjsonandjsonbvalues.

Many of these functions and operators will convert Unicode escapes in JSON strings to the appropriate single character. This is a non-issue if the input is typejsonb, because the conversion was already done; but forjsoninput, this may result in throwing an error, as noted in.

See alsofor the aggregate functionjson_aggwhich aggregates record values as JSON, and the aggregate functionjson_object_aggwhich aggregates pairs of values into a JSON object, and theirjsonbequivalents,jsonb_aggandjsonb_object_agg.

Table 9.43
Section 8.14
Table 9.1
Section 8.14.4
Table 9.44
Section 8.14.3
Section 8.14.4
Table 9.45
hstore
Table 9.46
Section 8.14
Section 9.20