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What are Operators?

Operators are symbols that compare or calculate values in SQL.

1. Comparison Operators

Used in WHERE to filter data:

SELECT * FROM students WHERE age = 20;   -- Equal
SELECT * FROM students WHERE age != 20;  -- Not equal
SELECT * FROM students WHERE age > 20;   -- Greater than
SELECT * FROM students WHERE age < 20;   -- Less than
SELECT * FROM students WHERE age >= 20;  -- Greater or equal
SELECT * FROM students WHERE age <= 20;  -- Less or equal

2. Logical Operators

Combine multiple 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';

NOT - Reverse the condition:

SELECT * FROM students WHERE NOT grade = 'A';

3. Special Operators

BETWEEN - Range of values:

SELECT * FROM students WHERE age BETWEEN 18 AND 25;

IN - Match a list:

SELECT * FROM students WHERE grade IN ('A', 'B', 'C');

LIKE - Pattern matching:

SELECT * FROM students WHERE name LIKE 'J%';   -- Starts with J
SELECT * FROM students WHERE name LIKE '%n';   -- Ends with n

IS NULL - Check for empty:

SELECT * FROM students WHERE grade IS NULL;

4. Math Operators

SELECT name, age + 5 AS age_in_5_years FROM students;  -- Add
SELECT name, price * 2 AS double_price FROM products;  -- Multiply

Quick Reference

Comparison: = != > < >= <=
Logical: AND OR NOT
Special: BETWEEN IN LIKE IS NULL
Math: + - * /

Tip: Use parentheses () to group conditions: WHERE (grade = 'A' OR grade = 'B') AND age > 20

Practice: Combine Conditions

Find students older than 20 with grade A. Try changing AND to OR!

SQL Editor

Output

Click "Run Query" to see results

Practice: Math Operations

Calculate age in 5 years. Try other math like age * 2!