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