หน้านี้ยังไม่พร้อมใช้งานในภาษาท้องถิ่นของคุณ เรากำลังพยายามอย่างหนักเพื่อเพิ่มเวอร์ชันภาษาอื่น ๆ เพิ่มเติม ขอบคุณสำหรับการสนับสนุนเสมอมา

Compute
Elastic Cloud Server
Huawei Cloud Flexus
Bare Metal Server
Auto Scaling
Image Management Service
Dedicated Host
FunctionGraph
Cloud Phone Host
Huawei Cloud EulerOS
Networking
Virtual Private Cloud
Elastic IP
Elastic Load Balance
NAT Gateway
Direct Connect
Virtual Private Network
VPC Endpoint
Cloud Connect
Enterprise Router
Enterprise Switch
Global Accelerator
Management & Governance
Cloud Eye
Identity and Access Management
Cloud Trace Service
Resource Formation Service
Tag Management Service
Log Tank Service
Config
OneAccess
Resource Access Manager
Simple Message Notification
Application Performance Management
Application Operations Management
Organizations
Optimization Advisor
IAM Identity Center
Cloud Operations Center
Resource Governance Center
Migration
Server Migration Service
Object Storage Migration Service
Cloud Data Migration
Migration Center
Cloud Ecosystem
KooGallery
Partner Center
User Support
My Account
Billing Center
Cost Center
Resource Center
Enterprise Management
Service Tickets
HUAWEI CLOUD (International) FAQs
ICP Filing
Support Plans
My Credentials
Customer Operation Capabilities
Partner Support Plans
Professional Services
Analytics
MapReduce Service
Data Lake Insight
CloudTable Service
Cloud Search Service
Data Lake Visualization
Data Ingestion Service
GaussDB(DWS)
DataArts Studio
Data Lake Factory
DataArts Lake Formation
IoT
IoT Device Access
Others
Product Pricing Details
System Permissions
Console Quick Start
Common FAQs
Instructions for Associating with a HUAWEI CLOUD Partner
Message Center
Security & Compliance
Security Technologies and Applications
Web Application Firewall
Host Security Service
Cloud Firewall
SecMaster
Anti-DDoS Service
Data Encryption Workshop
Database Security Service
Cloud Bastion Host
Data Security Center
Cloud Certificate Manager
Edge Security
Situation Awareness
Managed Threat Detection
Blockchain
Blockchain Service
Web3 Node Engine Service
Media Services
Media Processing Center
Video On Demand
Live
SparkRTC
MetaStudio
Storage
Object Storage Service
Elastic Volume Service
Cloud Backup and Recovery
Storage Disaster Recovery Service
Scalable File Service Turbo
Scalable File Service
Volume Backup Service
Cloud Server Backup Service
Data Express Service
Dedicated Distributed Storage Service
Containers
Cloud Container Engine
Software Repository for Container
Application Service Mesh
Ubiquitous Cloud Native Service
Cloud Container Instance
Databases
Relational Database Service
Document Database Service
Data Admin Service
Data Replication Service
GeminiDB
GaussDB
Distributed Database Middleware
Database and Application Migration UGO
TaurusDB
Middleware
Distributed Cache Service
API Gateway
Distributed Message Service for Kafka
Distributed Message Service for RabbitMQ
Distributed Message Service for RocketMQ
Cloud Service Engine
Multi-Site High Availability Service
EventGrid
Dedicated Cloud
Dedicated Computing Cluster
Business Applications
Workspace
ROMA Connect
Message & SMS
Domain Name Service
Edge Data Center Management
Meeting
AI
Face Recognition Service
Graph Engine Service
Content Moderation
Image Recognition
Optical Character Recognition
ModelArts
ImageSearch
Conversational Bot Service
Speech Interaction Service
Huawei HiLens
Video Intelligent Analysis Service
Developer Tools
SDK Developer Guide
API Request Signing Guide
Terraform
Koo Command Line Interface
Content Delivery & Edge Computing
Content Delivery Network
Intelligent EdgeFabric
CloudPond
Intelligent EdgeCloud
Solutions
SAP Cloud
High Performance Computing
Developer Services
ServiceStage
CodeArts
CodeArts PerfTest
CodeArts Req
CodeArts Pipeline
CodeArts Build
CodeArts Deploy
CodeArts Artifact
CodeArts TestPlan
CodeArts Check
CodeArts Repo
Cloud Application Engine
MacroVerse aPaaS
KooMessage
KooPhone
KooDrive
On this page

Show all

Manipulating tsvector

Updated on 2024-09-02 GMT+08:00

GaussDB(DWS) provides functions and operators that can be used to manipulate documents that are already in tsvector type.

  • tsvector || tsvector

    The tsvector concatenation operator returns a new tsvector which combines the lexemes and positional information of the two tsvectors given as arguments. Positions and weight labels are retained during the concatenation. Positions appearing in the right-hand tsvector are offset by the largest position mentioned in the left-hand tsvector, so that the result is nearly equivalent to the result of performing to_tsvector on the concatenation of the two original document strings. (The equivalence is not exact, because any stop-words removed from the end of the left-hand argument will not affect the result, whereas they would have affected the positions of the lexemes in the right-hand argument if textual concatenation were used.)

    One advantage of using concatenation in the tsvector form, rather than concatenating text before applying to_tsvector, is that you can use different configurations to parse different sections of the document. Also, because the setweight function marks all lexemes of the given tsvector the same way, it is necessary to parse the text and do setweight before concatenating if you want to label different parts of the document with different weights.

  • setweight(vector tsvector, weight "char") returns tsvector

    setweight returns a copy of the input tsvector in which every position has been labeled with the given weight, either A, B, C, or D. (D is the default for new tsvectors and as such is not displayed on output.) These labels are retained when tsvectors are concatenated, allowing words from different parts of a document to be weighted differently by ranking functions.

    NOTICE:

    Note that weight labels apply to positions, not lexemes. If the input tsvector has been stripped of positions then setweight does nothing.

  • length(vector tsvector) returns integer

    Returns the number of lexemes stored in the vector.

  • strip(vector tsvector) returns tsvector

    Returns a tsvector which lists the same lexemes as the given tsvector, but which lacks any position or weight information. While the returned tsvector is much less useful than an unstripped tsvector for relevance ranking, it will usually be much smaller.

เราใช้คุกกี้เพื่อปรับปรุงไซต์และประสบการณ์การใช้ของคุณ การเรียกดูเว็บไซต์ของเราต่อแสดงว่าคุณยอมรับนโยบายคุกกี้ของเรา เรียนรู้เพิ่มเติม

Feedback

Feedback

Feedback

0/500

Selected Content

Submit selected content with the feedback