MySQL — Where

Basic WHERE

SELECT * FROM users WHERE age > 18;

Comparison Operators

-- Equal
SELECT * FROM users WHERE name = 'John';

-- Not equal
SELECT * FROM users WHERE name != 'John';

-- Greater than
SELECT * FROM users WHERE age > 18;

-- Less than
SELECT * FROM users WHERE age < 30;

-- Greater than or equal
SELECT * FROM users WHERE age >= 18;

-- Less than or equal
SELECT * FROM users WHERE age <= 30;

Logical Operators

-- AND
SELECT * FROM users WHERE age > 18 AND age < 30;

-- OR
SELECT * FROM users WHERE age < 18 OR age > 60;

-- NOT
SELECT * FROM users WHERE NOT age < 18;

WHERE Examples

-- LIKE operator
SELECT * FROM users WHERE name LIKE 'John%';
SELECT * FROM users WHERE email LIKE '%@gmail.com';

-- IN operator
SELECT * FROM users WHERE age IN (18, 25, 30);

-- BETWEEN operator
SELECT * FROM users WHERE age BETWEEN 18 AND 30;

-- IS NULL
SELECT * FROM users WHERE age IS NULL;

-- IS NOT NULL
SELECT * FROM users WHERE email IS NOT NULL;

Mini Practice

Write MySQL code that:

1. Uses comparison operators
2. Uses logical operators
3. Uses LIKE operator
4. Uses IN and BETWEEN

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