SQL · Chapter 8 of 42

SQL UPDATE

UPDATE modifies existing rows. ALWAYS include a WHERE clause — without one, EVERY row is updated.

`UPDATE table SET col = value WHERE condition;`

Syntax

UPDATE table SET col = value WHERE condition;

Multiple columns

`SET col1 = val1, col2 = val2, ...`

You can reference other columns: `UPDATE products SET price = price * 1.1;`

Example 1 (sql)

UPDATE users SET age = 26 WHERE name = 'Ana';

Output

1 row updated

Change Ana's age.

Example 2 (sql)

UPDATE products SET price = price * 1.10 WHERE category = 'Books';

Output

3 rows updated

Bump prices by 10% for one category.

💡 Note: Before running an UPDATE, run the same WHERE clause as a SELECT to preview the affected rows.