The SUBSTR function in Oracle extracts a specific number of characters from a string. The syntax is SUBSTR(string, start_position, length), where string is the target string, start_position is the starting extraction position (starting from 1), and length is the number of characters extracted. A negative starting position means counting down from the end of the string, and omitting the length parameter extracts all characters from the starting position to the end of the string.
SUBSTR function in Oracle
SUBSTR function overview
The SUBSTR function is used to extract a specified number of characters from a given string. The syntax is as follows:
SUBSTR(string, start_position, length)
Where:
- string: The string from which characters are to be extracted.
- start_position: The position where you want to start extracting characters, starting from 1.
- length: The number of characters to extract.
SUBSTR function example
Suppose we have a string named "customer_name" whose value is "John Doe".
- Extract the first three characters: SUBSTR("customer_name", 1, 3) will return "Joh".
- Extract five characters starting from the fourth character: SUBSTR("customer_name", 4, 5) will return "n Doe".
- Extract the tüm characters starting from the third to last character: SUBSTR("customer_name", -3) will return "Doe".
Negative starting position
The starting position can be a negative number, which means counting down from the end of the string. For example:
- Extract the last four characters: SUBSTR("customer_name", -4) will return "Doe".
Missing length parameter
If the length parameter is omitted, the SUBSTR function will extract all characters from the starting position to the end of the string. For example:
- Extract the tüm characters starting from the sixth character: SUBSTR("customer_name", 6) will return "Doe".
Variations of the SUBSTR function
The SUBSTR function also has the following variants:
- INSTR: Used to find the first occurrence of a substring in a string.
- SUBSTRB: Used to extract characters starting from the specified byte position.
- SUBSTRC: is used to extract characters starting from the specified character position.
The above is the detailed content of substr usage in oracle. For more information, please follow other related articles on the PHP Chinese website!

The difference between MySQL and Oracle in performance and scalability is: 1. MySQL performs better on small to medium-sized data sets, suitable for fast scaling and efficient reading and writing; 2. Oracle has more advantages in handling large data sets and complex queries, suitable for high availability and complex business logic. MySQL extends through master-slave replication and sharding technologies, while Oracle achieves high availability and scalability through RAC.

Key features of Oracle software include multi-tenant architecture, advanced analytics and data mining, real-time application clustering (RAC), and automated management and monitoring. 1) A multi-tenant architecture allows for the management of multiple independent databases in one database instance, simplifying management and reducing costs. 2) Advanced analytics and data mining tools such as Oracle Advanced Analytics and OracleDataMining help extract insights from data. 3) Real-time application cluster (RAC) provides high availability and scalability, improving system fault tolerance and performance. 4) Automated management and monitoring tools such as Oracle EnterpriseManager (OEM) to automate daily maintenance tasks and monitor numbers in real time

Oracle has a profound impact in the fields of data management and enterprise applications. Its database is known for its reliability, scalability and security, and is widely used in industries such as finance, medical care and government. Oracle's influence has also expanded to middleware and cloud computing fields such as WebLogicServer and OracleCloudInfrastructure (OCI), providing innovative solutions. Despite the competition in the open source database and cloud computing market, Oracle maintains its leading position through continuous innovation.

Oracle's mission is to "help people see the value of data", and its core values include: 1) Customer first, 2) Integrity, 3) Innovation, and 4) Teamwork. These values guide Oracle's strategic decision-making and business innovation in the market.

Oracle Database is a relational database management system that supports SQL and object relational models to provide data security and high availability. 1. The core functions of Oracle database include data storage, retrieval, security and backup and recovery. 2. Its working principle involves multi-layer storage structure, MVCC mechanism and optimizer. 3. Basic usages include creating tables, inserting and querying data; advanced usages involve stored procedures and triggers. 4. Performance optimization strategies include the use of indexes, optimized SQL statements and memory management.

In addition to database management, Oracle software is also used in JavaEE applications, data grids and high-performance computing. 1. OracleWebLogicServer is used to deploy and manage JavaEE applications. 2. OracleCoherence provides high-performance data storage and caching services. 3. OracleExadata is used for high performance computing. These tools allow Oracle to play a more diversified role in the enterprise IT architecture.

Oracle is not only a database company, but also a leader in cloud computing and ERP systems. 1. Oracle provides comprehensive solutions from database to cloud services and ERP systems. 2. OracleCloud challenges AWS and Azure, providing IaaS, PaaS and SaaS services. 3. Oracle's ERP systems such as E-BusinessSuite and FusionApplications help enterprises optimize operations.

Oracle software applications in the real world include e-commerce platforms and manufacturing. 1) On e-commerce platforms, OracleDatabase is used to store and query user information. 2) In manufacturing, OracleE-BusinessSuite is used to optimize inventory and production planning.


Hot AI Tools

Undresser.AI Undress
AI-powered app for creating realistic nude photos

AI Clothes Remover
Online AI tool for removing clothes from photos.

Undress AI Tool
Undress images for free

Clothoff.io
AI clothes remover

Video Face Swap
Swap faces in any video effortlessly with our completely free AI face swap tool!

Hot Article

Hot Tools

Atom editor mac version download
The most popular open source editor

DVWA
Damn Vulnerable Web App (DVWA) is a PHP/MySQL web application that is very vulnerable. Its main goals are to be an aid for security professionals to test their skills and tools in a legal environment, to help web developers better understand the process of securing web applications, and to help teachers/students teach/learn in a classroom environment Web application security. The goal of DVWA is to practice some of the most common web vulnerabilities through a simple and straightforward interface, with varying degrees of difficulty. Please note that this software

VSCode Windows 64-bit Download
A free and powerful IDE editor launched by Microsoft

MantisBT
Mantis is an easy-to-deploy web-based defect tracking tool designed to aid in product defect tracking. It requires PHP, MySQL and a web server. Check out our demo and hosting services.

Zend Studio 13.0.1
Powerful PHP integrated development environment
