Comparison and Logical Operators

Building Up a Condition

A WHERE condition can combine tests with AND, OR, and NOT. BETWEEN a AND b covers an inclusive range, IN (…) checks membership in a list, and LIKE matches a text pattern where % stands for any run of characters.

GOAL

Build a compound WHERE condition and predict which rows pass.

SELECT * FROM products WHERE category_id IN (2, 3) returns how many rows?

CHECK IT

SELECT *
FROM products
WHERE category_id = 2 AND price < 900

Matches the condition (kept)abcDoesn't match (dropped)

products2 of 7 rows kept

id	name	category_id	price
1	Pixel Phone	2	799
2	iPhone	2	999
3	ThinkPad	3	1299
4	MacBook	3	1499
5	SQL Guide	5	39
6	DB Internals	6	55
7	Old Tablet	2	199

AND keeps only the rows where both conditions are true.