UPDATE
UPDATE changes existing rows that match a WHERE condition.
In this page:
Syntax
UPDATE table_name
SET column1 = value1, column2 = value2
WHERE condition;UPDATE
UPDATE table SET col = value [, ...] WHERE condition. Without WHERE every row is changed, so always check the condition first, ideally with a SELECT.
Values can be expressions using other columns, such as price = price * 1.1.
Wrap risky updates in a transaction.
Note:
Run the WHERE clause as a SELECT before running the UPDATE.
Example: UPDATE
CREATE TABLE products (id INTEGER PRIMARY KEY, name TEXT, price INTEGER, category TEXT);
INSERT INTO products VALUES (1, 'Pen', 3, 'office'), (2, 'Desk', 150, 'furniture'), (3, 'Notebook', 8, 'office');
UPDATE products SET price = price + 2 WHERE category = 'office';
SELECT name, price FROM products ORDER BY id;
UPDATE products SET category = 'stationery' WHERE name = 'Pen';
SELECT name, category FROM products ORDER BY id;
-- Output:
-- name | price
-- Pen | 5
-- Desk | 150
-- Notebook | 10
-- name | category
-- Pen | stationery
-- Desk | furniture
-- Notebook | officeLogin to try C/C++/Java/PHP code in the editor
Related Topics
Common Mistakes
- Forgetting the WHERE clause
- Updating with an ambiguous condition
- Not using a transaction for risky changes
Chapter Summary
- UPDATE SET changes columns
- WHERE picks the rows
- Without WHERE all rows change
- Values can be expressions
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