WHERE Clause

What is WHERE?

WHERE filters rows based on conditions. Like a search filter - only shows results that match your criteria.

How WHERE Works

Step-by-step:

SELECT * FROM students - Start with all rows
WHERE age > 20 - Apply the filter
Check each row - Is age greater than 20?
Result - Only matching rows returned

Basic Syntax

SELECT columns FROM table WHERE condition;

Comparison Operators

= Equal: WHERE age = 20
!= Not equal: WHERE grade != 'F'
> Greater than: WHERE age > 20
< Less than: WHERE age < 20
>= Greater or equal: WHERE age >= 20
<= Less or equal: WHERE age <= 20

Combining Conditions

-- AND: Both must be true
SELECT * FROM students WHERE age > 20 AND grade = 'A';

-- OR: Either can be true
SELECT * FROM students WHERE grade = 'A' OR grade = 'B';

Special Operators

-- BETWEEN: Range of values
SELECT * FROM students WHERE age BETWEEN 18 AND 25;

-- IN: Match any in list
SELECT * FROM students WHERE grade IN ('A', 'B');

-- LIKE: Pattern matching
SELECT * FROM students WHERE name LIKE 'A%';

Try WHERE Below

Use the playground to practice WHERE queries. Try:

SELECT * FROM students WHERE age > 20;
SELECT * FROM students WHERE grade = 'A';

What Comes Next

Next: Learn ORDER BY to sort your results.

Try WHERE

Filter data with conditions. Try: SELECT * FROM students WHERE age > 20;

Source Table: students

id	name	age	grade
1	Alice	20	A
2	Bob	22	B
3	Charlie	21	A
4	David	23	B

4 rows

SQL Editor