SQL – UPDATE Statement

The UPDATE statement allows you to update a single record or multiple records in a table.

The syntax for the UPDATE statement is:

UPDATE table
SET column = expression
WHERE predicates;

Example #1 - Simple example

Let's take a look at a very simple example.

UPDATE suppliers
SET name = 'HP'
WHERE name = 'IBM';

This statement would update all supplier names in the suppliers table from IBM to HP.

Example #2 - More complex example

You can also perform more complicated updates.

You may wish to update records in one table based on values in another table. Since you can't list more than one table in the UPDATE statement, you can use the EXISTS clause.

For example:

Whenever a supplier_id matched a customer_id value, the supplier_name would be overwritten to the customer name from the customers table.

Learn more about the EXISTS condition.

Practice Exercise #1

Based on the suppliers table populated with the following data, update the city to "Santa Clara" for all records whose supplier_name is "NVIDIA".

Solution:

The following SQL statement would perform this update.

The suppliers table would now look like this:

Practice Exercise #2

Based on the suppliers and customers table populated with the following data, update the city in the suppliers table with the city in the customers table when the supplier_name in the supplierstable matches the customer_name in the customers table.

Solution:

The following SQL statement would perform this update.

The suppliers table would now look like this: