Oracle系统函数、自定义函数、关键字，收集一些在工作中常用的Oracle知识点，不断的更新，不断的积累，就当作自己的记事本吧。
Oracle系统函数、自定义函数、关键字
[日期：2012-06-16] 来源：Linux社区 作者：baolong47 [字体：]
题记：收集一些在工作中常用的Oracle知识点，不断的更新，不断的积累，就当作自己的记事本吧。
一些关键字
1 IS NOT NULL，，判断字段否为空
2CASE WHEN．．． THEN ．．． ELSE ．．． END ，条件语句
3EXITS , NOT EXITS, 判断是否存在，通常放到WHERE 的后面
一些系统函数
1. TO_CHAR()
显示 ： 2012-06-15 10:11:45
2. TO_DATE() 转为为某种格式的时间
一些自定义函数
1. 写一个工作用到的函数CHECK_DEMAND_IS_NOTICE，该函数需传入一个NUMBER类型的数据，结果返回一个 VARCHAR2的类型数据
How do you alter a table in MySQL using the ALTER TABLE statement?Mar 19, 2025 pm 03:51 PMThe article discusses using MySQL's ALTER TABLE statement to modify tables, including adding/dropping columns, renaming tables/columns, and changing column data types.
How do I configure SSL/TLS encryption for MySQL connections?Mar 18, 2025 pm 12:01 PMArticle discusses configuring SSL/TLS encryption for MySQL, including certificate generation and verification. Main issue is using self-signed certificates' security implications.[Character count: 159]
How do you handle large datasets in MySQL?Mar 21, 2025 pm 12:15 PMArticle discusses strategies for handling large datasets in MySQL, including partitioning, sharding, indexing, and query optimization.
What are some popular MySQL GUI tools (e.g., MySQL Workbench, phpMyAdmin)?Mar 21, 2025 pm 06:28 PMArticle discusses popular MySQL GUI tools like MySQL Workbench and phpMyAdmin, comparing their features and suitability for beginners and advanced users.[159 characters]
How do you drop a table in MySQL using the DROP TABLE statement?Mar 19, 2025 pm 03:52 PMThe article discusses dropping tables in MySQL using the DROP TABLE statement, emphasizing precautions and risks. It highlights that the action is irreversible without backups, detailing recovery methods and potential production environment hazards.
How do you represent relationships using foreign keys?Mar 19, 2025 pm 03:48 PMArticle discusses using foreign keys to represent relationships in databases, focusing on best practices, data integrity, and common pitfalls to avoid.
How do you create indexes on JSON columns?Mar 21, 2025 pm 12:13 PMThe article discusses creating indexes on JSON columns in various databases like PostgreSQL, MySQL, and MongoDB to enhance query performance. It explains the syntax and benefits of indexing specific JSON paths, and lists supported database systems.
How do I secure MySQL against common vulnerabilities (SQL injection, brute-force attacks)?Mar 18, 2025 pm 12:00 PMArticle discusses securing MySQL against SQL injection and brute-force attacks using prepared statements, input validation, and strong password policies.(159 characters)
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
AI Hentai Generator
Generate AI Hentai for free.
Hot Article
Hot Tools
EditPlus Chinese cracked version
Small size, syntax highlighting, does not support code prompt function
MinGW - Minimalist GNU for Windows
This project is in the process of being migrated to osdn.net/projects/mingw, you can continue to follow us there. MinGW: A native Windows port of the GNU Compiler Collection (GCC), freely distributable import libraries and header files for building native Windows applications; includes extensions to the MSVC runtime to support C99 functionality. All MinGW software can run on 64-bit Windows platforms.
SublimeText3 Chinese version
Chinese version, very easy to use
PhpStorm Mac version
The latest (2018.2.1) professional PHP integrated development tool
SublimeText3 Linux new version
SublimeText3 Linux latest version
