SQL WHERE Clause

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🔎 Filtering Data

The SQL WHERE clause is used to filter records that meet specific conditions. Instead of returning the entire table, WHERE helps you narrow down results to only what you need.

This is one of the most powerful features in SQL because data filtering is at the heart of every real-world query.

1️⃣ Basic WHERE Example

Fetch employees who earn more than 60000:

SELECT FirstName, LastName, Salary
FROM Employees
WHERE Salary > 60000;

2️⃣ Using Equality (=)

SELECT * 
FROM Employees
WHERE Department = 'IT';

3️⃣ Multiple Conditions with AND / OR

SELECT * 
FROM Employees
WHERE Department = 'Sales' 
  AND Salary > 50000;

SELECT * 
FROM Employees
WHERE Department = 'HR' 
   OR Department = 'Finance';

4️⃣ NOT Operator

SELECT * 
FROM Employees
WHERE NOT Department = 'Admin';

5️⃣ Comparison Operators

Operator Description Example
= Equal WHERE Salary = 60000
<> or != Not Equal WHERE Department <> ‘IT’
> Greater Than WHERE Salary > 60000
< Less Than WHERE Salary < 30000
>= Greater or Equal WHERE Salary >= 40000
<= Less or Equal WHERE Salary <= 45000

6️⃣ Combining WHERE with ORDER BY

SELECT FirstName, Salary 
FROM Employees
WHERE Salary BETWEEN 50000 AND 80000
ORDER BY Salary DESC;
Pro Tip: Always use WHERE before ORDER BY, otherwise your query will throw an error.

✅ Key Takeaways

  • WHERE filters rows based on conditions.
  • Supports operators like =, !=, >, <, BETWEEN, LIKE.
  • Use AND / OR to combine multiple conditions.
  • NOT inverts a condition.
  • Always place WHERE before ORDER BY in SQL syntax.

📚 Continue Learning

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