DROP TABLE IF EXISTS scores;
SET NAMES utf8mb4;
CREATE TABLE scores (
value INT,
INDEX (value)
);
INSERT INTO scores VALUES (21);
INSERT INTO scores VALUES (21);
INSERT INTO scores VALUES (22);
SELECT count(*) FROM scores WHERE value >= 20;
count(*)
3
UPDATE scores SET value = 11 WHERE value = 21;
SELECT count(*) FROM scores WHERE value >= 20;
count(*)
1
DROP TABLE scores;
