📎 This article includes 2 downloadable practice files ↓

📘 SQL Beginner Course · Lesson 2 of 12

SELECT chooses columns; WHERE chooses rows. It’s the SQL version of the filter arrows in Excel, except you can save it, combine it and run it on millions of rows.

Comparisons

SELECT name, price FROM products WHERE price > 5000;
SELECT name, city  FROM customers WHERE region = 'South';
SELECT order_id    FROM orders WHERE status <> 'Delivered';   -- not equal (also !=)

Text and dates go in single quotes. Numbers don’t.

AND, OR and brackets

SELECT order_id, qty FROM orders
WHERE status = 'Delivered' AND qty >= 8;

SELECT name FROM customers
WHERE region = 'North' AND (city = 'Delhi' OR city = 'Jaipur');

IN: a list of values

SELECT order_id, status FROM orders WHERE status IN ('Pending', 'Shipped');
SELECT name FROM customers WHERE city NOT IN ('Delhi', 'Mumbai');

BETWEEN: ranges

SELECT order_id, order_date FROM orders
WHERE order_date BETWEEN '2026-07-01' AND '2026-07-15';

BETWEEN includes both ends. Dates in SQLite are stored as text in YYYY-MM-DD form, which sorts and compares correctly.

LIKE: patterns

In SQLite LIKE ignores case for English letters; in PostgreSQL use ILIKE for that.

NULL: missing values

SELECT name FROM customers WHERE gstin IS NULL;       -- no GSTIN recorded
SELECT name FROM customers WHERE gstin IS NOT NULL;

NULL means “unknown”, not zero or blank text. = NULL never matches anything; always use IS NULL.

Where beginners go wrong

Practice

Download shop.db and this lesson’s exercise file below. Open the database in the free DB Browser for SQLite (or sqlite3 shop.db), paste the exercises into the Execute SQL tab and write a query for each task. The expected result is printed under every task; answers are at the bottom of the file.