Updating rows

Updating rows is done using the UPDATE statement. Updates are done using two parts: defining which rows should be updated, and the values of the columns to replace with.

A lot of times an UPDATE statement will aim to replace one row, in which the query will use the primary key of the table to select the row to update.

Here is the syntax of an UPDATE statement:

UPDATE table_name
SET column1 = value1, column2 = value2, ...
WHERE key = value

Let's look at an example of how an UPDATE statement works.

CREATE TABLE customers (first_name NOT NULL, last_name NOT NULL, age);

INSERT INTO customers (first_name, last_name, age)
VALUES ("John", "Doe", 23), ("Eric", "Smith", 26);

SELECT * FROM customers;

UPDATE customers SET last_name = "Heart" WHERE first_name = "John";

SELECT * FROM customers;

Exercise

Add an update statement which updates Eric's age to 27 between the two SELECT statements.