2025年4月21日

摘要：阅读全文

posted @ 2025-04-21 10:23 ZhangZhihuiAAA 阅读(2) 评论(0) 推荐(0)

PostgreSQL - Install PostgreSQL and pgAdmin

摘要： 1️⃣ Install PostgreSQL sudo apt update sudo apt install postgresql postgresql-contrib ✅ This installs both the server and the psql CLI tool. zzh@ZZHPC 阅读全文

posted @ 2025-04-21 09:23 ZhangZhihuiAAA 阅读(9) 评论(0) 推荐(0)

PostgreSQL - Cursor

摘要： Cursors in PostgreSQL are used to process query results row by row, which is useful when you can’t—or don’t want to—handle the entire result set at on 阅读全文

posted @ 2025-04-21 08:59 ZhangZhihuiAAA 阅读(22) 评论(0) 推荐(0)

PostgreSQL - Difference between Utility Functions and Aggregate Functions

摘要： 🔹 GREATEST(): Function Returns the largest value from a list of expressions within a row. ✅ Usage: SELECT GREATEST(10, 20, 5); -- Returns 20 📌 In a 阅读全文

posted @ 2025-04-21 08:53 ZhangZhihuiAAA 阅读(2) 评论(0) 推荐(0)

SQL - Correlated Subquries

摘要：阅读全文

posted @ 2025-04-21 08:17 ZhangZhihuiAAA 阅读(2) 评论(0) 推荐(0)


博客园 © 2004-2025 浙公网安备 33010602011771号浙ICP备2021040463号-3

导航

2025年4月21日