MySQL Bugs: #27687: ALTER TABLE ... CONVERT TO uses @@collation

Bug #27687	ALTER TABLE ... CONVERT TO uses @@collation_database
Submitted:	6 Apr 2007 12:47	Modified:	9 Apr 2007 15:19
Reporter:	Alexander Nozdrin	Email Updates:
Status:	Verified	Impact on me:	None
Category:	MySQL Server: Charsets	Severity:	S3 (Non-critical)
Version:	5.0.40-BK	OS:	Any
Assigned to:	Assigned Account	CPU Architecture:	Any

Description:
ALTER TABLE ... CONVERT TO CHARSET DEFAULT uses @@collation_database
variable (character set of the current db) in its job.

Although The Manual (http://dev.mysql.com/doc/refman/5.0/en/alter-table.html)
does not explicitly states what should be used in this case, I think,
default database character set should be used. Otherwise, this statement
depends on the current database (the value of @@collation_database),
which seems to be inadequate to me.

How to repeat:
CREATE DATABASE db1 CHARACTER SET latin1;
use db1;

CREATE DATABASE db2 CHARACTER SET utf8;
CREATE TABLE db2.t1(s CHAR(10));
INSERT INTO db2.t1 VALUES('a');
SELECT CHARSET(s) FROM db2.t1; --> utf8;

ALTER TABLE db2.t1 CONVERT TO CHARSET DEFAULT;
SELECT CHARSET(s) FROM db2.t1; --> latin1;

"default database character set should be used" -- I mean,
the character set of the database which is being altered.

Thank you for a problem report. I am not sure is it a bug or a feature request, but I verified current behaviour just as described wiht latest 5.0.40-BK on Linux.