WHERE Clause

SELECT columns
FROM table
WHERE condition;

-- Exact match
SELECT * FROM users WHERE status = 'active';

-- Numeric comparison
SELECT * FROM products WHERE price > 100;

-- Date comparison
SELECT * FROM orders WHERE created_at > '2024-01-01';

-- AND: All conditions must be true
SELECT * FROM users 
WHERE status = 'active' 
  AND country = 'USA'
  AND age >= 18;

-- OR: Any condition can be true
SELECT * FROM products 
WHERE category = 'Electronics' 
   OR category = 'Computers';

-- Combining AND and OR
SELECT * FROM orders 
WHERE status = 'pending' 
  AND (total > 100 OR priority = 'high');

-- Filter on calculated values
SELECT * FROM order_items 
WHERE price * quantity > 500;

-- Filter using functions
SELECT * FROM users 
WHERE LENGTH(name) > 10;

-- Filter using LOWER/UPPER for case-insensitive search
SELECT * FROM products 
WHERE LOWER(name) = 'iphone';