MySQL Bugs: #94433: In mysql 8.0, result set of "group by" query is not sorted

Bug #94433	In mysql 8.0, result set of "group by" query is not sorted
Submitted:	22 Feb 1:15	Modified:	22 Feb 6:59
Reporter:	SeWoong Jeon	Email Updates:
Status:	Not a Bug	Impact on me:	None
Category:	MySQL Server: Optimizer	Severity:	S3 (Non-critical)
Version:	8.0.15	OS:	CentOS (CentOS 7.5)
Assigned to:		CPU Architecture:	x86 (x86_64)
Tags:	regression

Description:
In mysql 8.0, result set of "group by" query is not sorted.

mysql> select user, count(*) from mysql.user group by user;
+------------------+----------+
| user             | count(*) |
+------------------+----------+
| sbtest           |        2 | (!!)
| dbtest           |        2 |
| mysql.infoschema |        1 |
| mysql.session    |        1 |
| mysql.sys        |        1 |
| root             |        1 |
+------------------+----------+
6 rows in set (0.00 sec)

How to repeat:
.

Suggested fix:
sort the result set.

Hello SeWoong Jeon,

Thank you for the report.

regards,
Umesh

My colleague Shane pointed out that this is expected behavior and not a bug. Quoting from our manual - The deprecated ASC or DESC qualifiers for GROUP BY clauses are removed. Queries that previously relied on GROUP BY sorting may produce results that differ from previous MySQL versions. To produce a given sort order, provide an ORDER BY clause.

https://dev.mysql.com/doc/refman/8.0/en/mysql-nutshell.html