SQL Operators 🧮

Mentor's Note: Operators are the verbs of your query logic. They define how you want to filter, calculate, or compare your data. Without them, you can only fetch raw lists. 💡

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🌟 The Scenario: The Online Store 🛒

Imagine you run an e-commerce site. You need to filter products.

1. Arithmetic: "Calculate the price after a 10% discount." (Price * 0.9)
2. Comparison: "Show products cheaper than ₹500." (Price < 500)
3. Logical: "Show items that are Red AND Large." (Color = 'Red' AND Size = 'L')

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🎨 Visual Logic: Operator Types

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💻 1. Arithmetic Operators (Math) ➕

Used to perform mathematical operations on numeric data.

Operator	Description	Example	Result
+	Add	SELECT 10 + 5;	15
-	Subtract	SELECT 10 - 5;	5
*	Multiply	SELECT 10 * 5;	50
/	Divide	SELECT 10 / 5;	2
%	Modulus (Remainder)	SELECT 10 % 3;	1

-- Scenario: Calculate Annual Salary
SELECT salary * 12 AS annual_salary FROM employees;

💻 2. Comparison Operators (Testing) ⚖️

Used to compare two values. Returns TRUE or FALSE.

Operator	Description	Example
=	Equal to	WHERE salary = 50000
<> or !=	Not equal to	WHERE dept <> 'HR'
>	Greater than	WHERE age > 18
<	Less than	WHERE price < 100
>=	Greater than or equal	WHERE rating >= 4.5
<=	Less than or equal	WHERE stock <= 10

-- Scenario: Find High Value Products
SELECT * FROM products WHERE price > 1000;

💻 3. Logical Operators (Combiners) 🔗

Used to combine multiple conditions.

Operator	Description	Logic
AND	TRUE if all conditions are TRUE	Red AND Large (Must be both)
OR	TRUE if any condition is TRUE	Red OR Blue (Can be either)
NOT	Reverses the result	NOT Red (Anything but Red)

-- Scenario: Find specific shoes
SELECT * FROM shoes 
WHERE (color = 'Black' OR color = 'Brown') 
AND size = 10;

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💡 Operator Precedence (BODMAS for SQL)

When combining operators, SQL follows a strict order:

1. Parentheses ()
2. Multiplication/Division * /
3. Addition/Subtraction + -
4. NOT
5. AND
6. OR

Rule of Thumb: Always use Parentheses () when mixing AND/OR to ensure clarity!

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📈 Learning Path

• ← Back: SQL Commands
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