Lesson 10: Updating Data

20 min read Beginner Lesson 10 of 12 7.9k learners

Introduction

The UPDATE statement is used to modify existing records in a table. You can update one row, multiple rows, or even all rows depending on the WHERE clause.

Updating a Single Row

Use UPDATE with WHERE to modify a specific row.

SQL

UPDATE customers
SET email = 'new.email@email.com'
WHERE customer_id = 3;

Updating Multiple Rows

If the WHERE condition matches multiple rows, all of them will be updated.

SQL

UPDATE customers
SET city = 'New York'
WHERE city = 'Boston';

Updating with Expressions

You can use expressions in SET to update values dynamically.

SQL

UPDATE employees
SET salary = salary * 1.1
WHERE department = 'Sales';

Updating with Subqueries

You can set a column value based on a subquery result.

SQL

UPDATE employees
SET department_id = (
    SELECT department_id 
    FROM departments 
    WHERE name = 'HR'
)
WHERE employee_id = 10;