mysql - 为什么删除了 3 行的 sql 查询拼图？

Question

谁能告诉我这其中的技术原因？

CREATE TABLE test (
  id varchar(3) NOT NULL,
  PRIMARY KEY  (id)
);

INSERT INTO test VALUES ('0'), ('1'), ('2'), ('ab'), ('bb');

select * from test;

DELETE FROM test WHERE id=0;

Which Deletes 3 rows from table test.

Answer 1

因为这个:

SELECT 0 = 'ab';
+----------+
| 0 = 'ab' |
+----------+
|        1 |
+----------+

要删除确切的行，请使用 BINARY 运算符，它将强制逐字节比较 -

DELETE FROM test WHERE id = BINARY 0;