Bug #99359 Order by in group_concat with prepare statement returns unexpected results

• Submitted: 26 Apr 2020 10:57
• Modified: 27 Apr 2020 12:41
• Reporter: Feng Liyuan
• Status: Verified
• Category: MySQL Server: Prepared statements
• Severity: S3 (Non-critical)
• Version: 5.6.47, 5.7.29, 8.0.19
• OS: Any
• CPU Architecture: Any

[26 Apr 2020 10:57] Feng Liyuan

Description:
Order by in group_concat with prepare statement and column positions returns different results.

How to repeat:
drop table if exists test;
create table test(id int, name int);
insert into test values(1, 10);
insert into test values(1, 20);
insert into test values(1, 30);
insert into test values(2, 20);
insert into test values(3, 200);
insert into test values(3, 500);

prepare s1 from "select group_concat(name, id ORDER BY ? desc, name) from test";

set @a=3;
execute s1 using @a;   -- returns error, as expected

set @a=2;
execute s1 using @a;

set @a=3;
execute s1 using @a;   -- unexpected, should returns error like before

[27 Apr 2020 12:41] MySQL Verification Team

Hello Feng Liyuan,

Thank you for the report and feedback.

regards,
Umesh