Category: PostgreSQL

PostgreSQL UPDATE ☕✏️ You’ve already: Created tables Inserted rows Selected / read data Added columns to existing tables Now the real world hits: students change phone numbers, GPAs get updated after revaluation, enrollment status...

PostgreSQL ALTER COLUMN — one of the most frequently used (and sometimes most nerve-wracking) commands when your database schema needs to evolve after data is already inside. You’ve already learned: CREATE TABLE INSERT SELECT...

PostgreSQL DROP COLUMN ☕🗑️ You’ve already learned how to: Create tables Add columns Modify columns (ALTER COLUMN) Update data Now comes the opposite direction: removing a column you no longer need (maybe it was...

PostgreSQL: DELETE ☕🗑️ You’ve already learned how to: Create tables Insert rows Select / read data Update existing rows Add, alter, drop columns Now comes DELETE — the command that permanently removes rows from...

PostgreSQL DROP TABLE ☕💥 You’ve already learned: CREATE TABLE INSERT, SELECT, UPDATE, DELETE ALTER TABLE … ADD / ALTER / DROP COLUMN Now comes the command that says: “I no longer want this table...

create a complete demo database from scratch! ☕🎬 Up to now we’ve been building tiny pieces (one table → few rows → simple queries). Today we build a realistic mini-project database that feels like...

PostgreSQL Syntax. When people say “PostgreSQL syntax”, they usually mean one (or a mix) of these things: The general rules how SQL commands must be written in PostgreSQL (lexical structure, keywords, identifiers, quoting, case...

PostgreSQL: Operators ☕🔧 When people say “PostgreSQL operators”, they usually mean all the special symbols and short keywords that you put between values to compare them, combine them, do math with them, check membership,...

Part 1: What is the SELECT Statement? At its core, the SELECT statement is how you retrieve data from a PostgreSQL database . It’s the “R” in CRUD (Create, Read, Update, Delete) operations. When you use SELECT, you’re...

Part 1: What is SELECT DISTINCT? The SELECT DISTINCT clause removes duplicate rows from your query results, returning only unique combinations of the selected columns. The Basic Syntax sql

When you use DISTINCT, PostgreSQL compares each...