restore

42749	72	VOLN ADSL

44205	72	VOLN ADSL

DROP TABLE t1;

create table t1(a char(200) collate utf8_unicode_ci NOT NULL default '')

default charset=utf8 collate=utf8_unicode_ci;

insert into t1 values (unhex('65')), (unhex('C3A9')), (unhex('65'));

explain select distinct a from t1;

id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra

1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	3	Using temporary

select distinct a from t1;

a

e

explain select a from t1 group by a;

id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra

1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	3	Using temporary; Using filesort

select a from t1 group by a;

a

e

drop table t1;

CREATE TABLE t1(id varchar(20) NOT NULL) DEFAULT CHARSET=utf8;

INSERT INTO t1 VALUES ('xxx'), ('aa'), ('yyy'), ('aa');

SELECT id FROM t1;