Problem

Given a table with the following schema:
CREATE TABLE foo (
id INT NOT NULL,
value INT NOT NULL,
status INT NOT NULL
);
Write a SQL query that will lock the table for writing, update all rows with a status of 0 to 1, and then unlock the table.
Example input:
id | value | status
1 | 10 | 0
2 | 20 | 0
3 | 30 | 0
4 | 40 | 0
5 | 50 | 0
Example output:
id | value | status
1 | 10 | 1
2 | 20 | 1
3 | 30 | 1
4 | 40 | 1
5 | 50 | 1

Solution

/*

Solution:

LOCK TABLE foo WRITE;
UPDATE foo SET status = 1 WHERE status = 0;
UNLOCK TABLES;

This solution is optimal because it locks the table for writing, updates all rows with a status of 0 to 1, and then unlocks the table.

*/