Category: PostgreSQL

Part 1: What is ORDER BY? The ORDER BY clause sorts the result set of a query by one or more columns, in ascending or descending order. It’s the last step in query execution (conceptually), organizing...

Part 1: What is the WHERE Clause? The WHERE clause filters rows from a table based on specified conditions. Only rows that satisfy the condition are included in the result set. The Basic Syntax sql

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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...

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...

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,...

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...

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 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...

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 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...