Essential PostgreSQL SQL Commands Reference

Version Information show server_version; Insert Operations Bulk Insert from SELECT Insert records from one table into another using SELECT: INSERT INTO target_table (uuid_column, relation_id, relation_name) SELECT replace(cast(uuid_generate_v4() AS VARCHAR), '-', ''), id, name FROM source_table; Auto-Increment Primary Key Creat ...

Posted on Mon, 19 Oct 2026 16:34:34 +0000 by Hell Toupee

Frequently Asked SQL Problems on Leetcode

1757. Products With High Fat and Recylcable Flag Initial attempt: SELECT product_id FROM Products WHERE low_fats == 'Y' AND recyclable == 'Y' Corrected version: SELECT product_id FROM Products WHERE low_fats = 'Y' AND recyclable = 'Y' 584. Find Customer Referee Initial attempt: SELECT DISTINCT name FROM Customer WHERE referee_id != 2 Revised ...

Posted on Mon, 05 Oct 2026 16:52:36 +0000 by elacdude

Getting Started with LINQ in .NET

Language Integrated Query (LINQ), introduced in .NET Framework 3.5 and Visual Studio 2008, provides a unified query syntax directly in C# for working with data across different sources. It operates on any collection implementing IEnumerable<T> and returns a new enumerable sequence, leveraging deferred execution in many cases. Consider a t ...

Posted on Mon, 21 Sep 2026 16:46:30 +0000 by lzylzlz

SQL Query Essentials: From Basic Selection to Complex Joins

Selecitng Data Basic SELECT Statements SELECT * FROM customers WHERE customer_id = 1 ORDER BY first_name; Selecting Specific Columns SELECT first_name, last_name, points, points + 10, points / 10 + 100, (points + 10) * 100 AS discount_factor, (points + 10) * 100 AS 'discount factor' FROM customers; Note: Use ...

Posted on Mon, 14 Sep 2026 16:04:42 +0000 by marque

MySQL SQL Fundamentals and Query Operations

SQL Overview SQL (Structured Query Language) serves as the standard communication protocol for relational database systems. It provides a comprehensive command set specifically designed for database operations, enabling users to issue declarative instructions without worrying about implementation details. SQL Syntax Standards SQL keywords are ...

Posted on Thu, 03 Sep 2026 16:01:25 +0000 by BrianWald

Passing Parameters in Vue Router: params vs query

In Vue Router, you can pass parameters between routes using two main mechanisms: params and query. Understanding their differences is crucial for building robust navigation in Vue applications. A key distinction is that params are not visible in the URL, while query parameters appear as query strings (?key=value). This affects behavior on page ...

Posted on Sun, 19 Jul 2026 16:41:10 +0000 by AKalair

Mastering Data Query Language in MySQL

Core Concepts of DQL Data Query Language (DQL) primarily utilizes the SELECT statement for retrieving information from databases. This functionality forms the backbone of database operations, enabling both simple single-table queries and complex multi-table joins with nested conditions. SELECT Statement Structure SELECT [ALL | DISTINCT] { * | t ...

Posted on Tue, 30 Jun 2026 18:07:15 +0000 by Ryanz

MySQL Fundamentals and Common Operations

After a prolonged break from coding, I found myself struggling to recall basic SQL syntax 😅 Reviewing my old SQL notes and adding some updates 😂 Primary references: MySQL Documentation: https://dev.mysql.com/doc/refman/8.0/en/tutorial.html Yi Bai Tutorial: https://www.yiibai.com/mysql "Learning SQL" by Alan Beaulieu Basic Operatio ...

Posted on Tue, 09 Jun 2026 17:12:16 +0000 by tidalwave

FastAPI Parameter Declaration Quick Reference

Query Parameters from fastapi import Query username: str = Query(..., title="User name", min_length=5, max_length=30) Detail Example Purpose Extracts values from the URL query string URL Pattern /items?username=alice Required/Optional Query(...) required; Query(None) optional Default role: str = Query("user") ...

Posted on Wed, 03 Jun 2026 17:04:25 +0000 by duhhh33

Oracle Database Query Techniques and Object Management

1. String Concatenation Operator SELECT 'Employee: ' || ename || ', Role: ' || job || ', Salary: ' || sal AS details FROM emp; 2. Convert Strings to Lowercase SELECT LOWER(ename) AS lowercase_name FROM emp; 3. Value Replacmeent SELECT DECODE(deptno, 10, 'Development', 20, 'Product', 30, 'Maintenance') AS department FROM emp; 4. Extract Curre ...

Posted on Mon, 18 May 2026 11:54:38 +0000 by vponz