SQL WHERE Clause: Syntax, Examples & Practice

WHERE is how you tell a database which rows you want. The database checks your condition against every row in the table: rows where the condition is true are kept, and rows where it is false — or unknown, because of a NULL value — are skipped. Leave WHERE out and the statement applies to every row.

• SELECT … WHERE returns only the matching rows.
• UPDATE … WHERE changes only the matching rows.
• DELETE … WHERE removes only the matching rows.

Basic WHERE Syntax

SELECT column1, column2
FROM table_name
WHERE condition;

The condition is usually a column, an operator and a value — for example marks > 80.

A Simple WHERE Example

SELECT *
FROM students
WHERE marks > 80;

The query reads the students table and keeps only the rows where marks is greater than 80. Priya, Aman and Alice are returned; Bob (42) and Karan (76) are filtered out. The * means "all columns", so WHERE decides which rows appear, not which columns.

Think of WHERE as a Filter

WHERE with UPDATE and DELETE

WHERE works the same way when you change data: it picks the rows the statement is allowed to touch.

-- Change only the rows that match
UPDATE students
SET class = 11
WHERE class = 10;

-- Remove only the rows that match
DELETE FROM students
WHERE marks < 35;

Where Is WHERE Used in Real Systems?

The exact structure SQL expects — get this right every time

Every WHERE condition follows the same pattern: a column, an operator, and a value.

SELECT column1, column2
FROM table_name
WHERE column_name operator value;

• SELECT comes first — pick which columns (new to SELECT? start with the BIG 6 SQL clauses)
• FROM comes second — pick which table
• WHERE comes third — define the filter condition
• A condition follows the pattern: column operator value
• Text values need single quotes: 'Delhi', 'Active'
• Numbers and booleans need no quotes: 80, 10, true (see SQL data types)

Multiple Conditions Syntax

-- Both conditions must be true (AND)
SELECT *
FROM students
WHERE class = 10 AND marks > 75;

-- Either condition can be true (OR)
SELECT *
FROM students
WHERE city = 'Delhi' OR city = 'Mumbai';

Where WHERE Goes: SQL Clause Order

SELECT *
WHERE marks > 80
FROM students;

SELECT *
FROM students
WHERE marks > 80;

WHERE is written third. It comes after FROM — including any SQL JOINs that combine tables — and before GROUP BY, HAVING and ORDER BY. That is why WHERE filters individual rows before any grouping or sorting happens.

Filtering numbers, text and dates — the three things you'll do most

WHERE with Numbers

Numeric values are written without quotes and work with every comparison operator.

SELECT *
FROM students
WHERE class = 10;

SELECT *
FROM products
WHERE price < 500;

WHERE with Text

Text values go inside single quotes. The match is exact — 'Delhi' does not match 'New Delhi'. For partial matches, use the SQL LIKE operator.

SELECT *
FROM students
WHERE city = 'Delhi';

WHERE with Dates

Dates are written as quoted strings in 'YYYY-MM-DD' format and can be compared like numbers — earlier dates are "less than" later ones. To extract a year or month before filtering, see SQL date functions.

SELECT *
FROM orders
WHERE order_date BETWEEN
  '2026-01-01' AND '2026-06-01';

Your tools for filtering — pick an operator, or expand any of them below

SELECT *
FROM students
WHERE class = 10;

SELECT *
FROM students
WHERE class != 10;

SELECT *
FROM students
WHERE marks > 80;

SELECT *
FROM students
WHERE marks < 50;

SELECT *
FROM students
WHERE marks >= 80;

SELECT *
FROM products
WHERE price <= 500;

SELECT *
FROM students
WHERE marks BETWEEN 70 AND 90;

SELECT *
FROM students
WHERE name LIKE 'A%';

SELECT *
FROM students
WHERE class IN (9, 10);

Combine conditions — this is where SQL WHERE gets really powerful

SELECT *
FROM students
WHERE class = 10
  AND marks > 80;

SELECT *
FROM students
WHERE class = 10
  OR class = 9;

Combining AND + OR — Use Parentheses

SELECT *
FROM users
WHERE is_premium = 1
  AND city = 'Houston'
  OR city = 'Austin';
-- Returns: (premium AND Houston) OR anyone in Austin: 13 users

SELECT *
FROM users
WHERE is_premium = 1
  AND (city = 'Houston'
    OR city = 'Austin');
-- Returns: premium users in Houston or Austin: 7 users

Checking one column against several values? city IN ('Houston', 'Austin') says the same thing as the OR above with less typing — see filtering multiple values with WHERE IN.

The most misunderstood part of SQL WHERE — NULL is not zero

The Golden Rule: Never Use = NULL

SELECT *
FROM employees
WHERE manager_id = NULL;
-- NULL = NULL is NULL, not TRUE
-- So no rows match

SELECT *
FROM employees
WHERE manager_id IS NULL;
-- Returns employees with
-- no assigned manager

IS NOT NULL — Finding Rows That Have a Value

-- Employees who have a manager
SELECT first_name, last_name, manager_id
FROM employees
WHERE manager_id IS NOT NULL;   -- 110 of 120 employees

-- Orders that have shipped
SELECT id, status, shipped_date
FROM orders
WHERE shipped_date IS NOT NULL; -- 103 of 200 orders

Why Does = NULL Fail?

Real Business Examples

-- Orders that haven't been shipped yet
SELECT id, total
FROM orders
WHERE shipped_date IS NULL;     -- 97 orders

-- Employees with no manager (the top of the org chart)
SELECT first_name, last_name, department
FROM employees
WHERE manager_id IS NULL;       -- 10 employees

Filtering NULLs out is one option; replacing them with a default value is another. That is what the COALESCE function is for.

One of the most common SQL interview questions — know this cold

Side-by-Side Comparison

WHERE — Filter Before Grouping

-- Step 1: WHERE removes rows with marks ≤ 50
-- Step 2: GROUP BY groups remaining rows by class
-- Step 3: AVG() is calculated on the filtered rows
SELECT class, AVG(marks) AS avg_marks
FROM students
WHERE marks > 50
GROUP BY class;

HAVING — Filter After Grouping

-- Step 1: GROUP BY groups ALL rows by class
-- Step 2: COUNT(*) counts each group
-- Step 3: HAVING removes groups with fewer than 5 students
SELECT class, COUNT(*) AS total_students
FROM students
GROUP BY class
HAVING COUNT(*) >= 5;

Using Both Together

-- WHERE filters failing students first (marks > 40)
-- GROUP BY groups passing students by class
-- HAVING keeps only classes with 5 or more students
SELECT class, COUNT(*) AS passing_students
FROM students
WHERE marks > 40
GROUP BY class
HAVING COUNT(*) >= 5;

Pattern matching — search text columns with wildcards

The Two Wildcards

LIKE Examples

-- First names starting with 'A'
SELECT first_name, last_name FROM users WHERE first_name LIKE 'A%';
-- 14 users: Anthony, Angela, Amy, Andrew, Amanda, Ashley ...

-- Last names ending with 'son'
SELECT first_name, last_name FROM users WHERE last_name LIKE '%son';
-- 14 users: Jackson, Wilson, Robinson, Johnson, Anderson, Nelson ...

-- Email addresses from Gmail
SELECT first_name, email FROM users WHERE email LIKE '%@gmail.com';
-- 28 users

-- Product names containing 'phone'
SELECT name FROM products WHERE name LIKE '%phone%';
-- Magnetic Phone Mount Pro, Noise-Cancelling Headphones

-- First names whose second letter is 'a'
SELECT first_name FROM users WHERE first_name LIKE '_a%';
-- 41 users: Barbara, Carol, David, James, Karen, Laura ...

NOT LIKE — Exclude Patterns

-- Find all products that are NOT electronics
SELECT * FROM products
WHERE category NOT LIKE '%electronics%';

-- Exclude test accounts
SELECT * FROM users
WHERE email NOT LIKE '%test%'
  AND email NOT LIKE '%example%';

Avoid these — every SQL beginner makes them at least once

SELECT *
WHERE marks > 80
FROM students;

SELECT *
FROM students
WHERE marks > 80;

SELECT *
FROM employees
WHERE manager_id = NULL;

SELECT *
FROM employees
WHERE manager_id IS NULL;

SELECT *
FROM students
WHERE city = 'Delhi'
  AND city = 'Mumbai';

SELECT *
FROM students
WHERE city = 'Delhi'
  OR city = 'Mumbai';

SELECT *
FROM students
WHERE name = Priya;

SELECT *
FROM students
WHERE name = 'Priya';

SELECT class, COUNT(*)
FROM students
WHERE COUNT(*) > 10
GROUP BY class;

SELECT class, COUNT(*)
FROM students
GROUP BY class
HAVING COUNT(*) > 10;

WHERE is_premium = 1
  AND city = 'Houston'
  OR city = 'Austin'

WHERE is_premium = 1
  AND (city = 'Houston'
    OR city = 'Austin')

Learn → Practice — write the queries yourself

These five exercises use the tables in the SQLabHub SQL Playground (products, employees, orders and users). Write each query yourself first, run it, then compare it with the solution.

1. 1Find every product that costs less than 50.

   Show solution

   SQL

   SELECT name, price
   FROM products
   WHERE price < 50;

2. 2List employees whose salary is between 50000 and 80000.

   Show solution

   SQL

   SELECT first_name, last_name, salary
   FROM employees
   WHERE salary BETWEEN 50000 AND 80000;

3. 3Show orders that have not been shipped yet.

   Show solution

   SQL

   SELECT id, order_date, status
   FROM orders
   WHERE shipped_date IS NULL;

4. 4Find users with a Gmail address.

   Show solution

   SQL

   SELECT first_name, email
   FROM users
   WHERE email LIKE '%@gmail.com';

5. 5List products rated 4 or higher that are also priced under 100.

   Show solution

   SQL

   SELECT name, price, rating
   FROM products
   WHERE rating >= 4
     AND price < 100;

Beginner to intermediate — with model answers