Bug #120576 drop index can lead to different results

• Submitted: 30 May 7:15
• Reporter: fan liu
• Status: Open
• Category: MySQL Server: MyISAM storage engine
• Severity: S3 (Non-critical)
• Version: 8.0.45
• OS: Any
• CPU Architecture: Any

[30 May 7:15] fan liu

Description:
The same query returned different results after I dropped the index.
SELECT  t1.c0, t0.c0 FROM t1, t0 WHERE (t0.c0) IN (IF(-939664372, t1.c0, '1202071427'));
c0|c0|
--+--+
drop INDEX i0 ON t0;

SELECT  t1.c0, t0.c0 FROM t1, t0 WHERE (t0.c0) IN (IF(-939664372, t1.c0, '1202071427'));
c0        |c0        |
----------+----------+
-191432000|-191432000|
 939810000| 939810000|

How to repeat:
DROP DATABASE IF EXISTS test;
CREATE DATABASE  test;
USE test;
 CREATE TABLE t0(c0 FLOAT, KEY `i0` (`c0`)) ENGINE=MyISAM ;

CREATE TABLE t1 LIKE t0;

INSERT INTO t1(c0) VALUES(-191432078),(939810017);

INSERT INTO t0(c0) VALUES(-191432078),(939810017),(NULL);

SELECT  t1.c0, t0.c0 FROM t1, t0 WHERE (t0.c0) IN (IF(-939664372, t1.c0, '1202071427'));

drop INDEX i0 ON t0;

SELECT  t1.c0, t0.c0 FROM t1, t0 WHERE (t0.c0) IN (IF(-939664372, t1.c0, '1202071427'));