CREATE TABLE & Data Types

Defining Tables

CREATE TABLE defines the structure of a new table — its columns, data types, and constraints. Choosing the right data types upfront saves a lot of pain later.

Common Data Types

• INTEGER / INT — whole numbers
• NUMERIC(p,s) / DECIMAL(p,s) — exact decimal numbers (use for money)
• FLOAT / REAL / DOUBLE — approximate floating-point (avoid for money)
• TEXT / VARCHAR(n) — variable-length strings
• CHAR(n) — fixed-length strings (padded with spaces)
• BOOLEAN — true/false
• DATE — calendar date (YYYY-MM-DD)
• TIMESTAMP — date + time (with optional timezone)

CREATE TABLE courses (
  id          INTEGER      PRIMARY KEY,
  title       VARCHAR(200) NOT NULL,
  category    VARCHAR(100),
  price       NUMERIC(8,2) NOT NULL DEFAULT 0,
  created_at  TIMESTAMP    NOT NULL DEFAULT CURRENT_TIMESTAMP
);