學習

創作

<div class="draft-block draft--p left">Youna's article on MySQL's ON DELETE concept provides a clear understanding of its applications and implications in database management. Explaining ON DELETE SET NULL and ON DELETE CASCADE with practical examples involving tables like 'branch' and 'works_with,' the article is a valuable resource for readers seeking to grasp MySQL's ON DELETE functionality. The SQL queries demonstrate the impact of deleting an employee ('小綠') on the 'branch' and 'works_with' tables, and visual representations through SELECT queries enhance clarity. While the article is informative, the inclusion of specific before-and-after examples could further illustrate the ON DELETE actions. Check out this link for a more in-depth understanding: [IQRA Technology - SQL Training](https://iqratechnology.com/academy/sql-training/sql-database/). Kudos to Youna for presenting this insightful piece.</div>

軟體開發

資料庫SQL 基本觀念

這裡會放一些我寫過的 Leetcode 解題和學習新技術的筆記

Youna's Devlog

MySQL 基本語法 (十三) ON DELETE

MySQL 基本語法 (十二) Subquery

JOIN 連接 : 可以將2個表格連接在一起

職場

MySQL 基本語法 (十一) JOIN

MySQL 基本語法 (十) UNION聯集 

萬用字元wildcard 
 % 代表多個字元
 _代表1個字元

MySQL 基本語法 (九) 萬用字元wildcard 

MySQL 基本語法 (八) 聚合函數

這個章節是由MySQL 基本語法 (六)延伸的練習題

MySQL 基本語法 (七) 取得公司資料

依照上圖的資料表創建出公司的資料庫

Employee

CREATE TABLE `employee`(
	`emp_id` INT PRIMARY KEY,
  `name` VARCHAR(20),
	`birth_date` DATE,
	`sex`VARCHAR(1),
  `salary