* mysql 콘솔에서 입력할경우 한글은 2byte

mysql> select length('안녕하세요')
    -> , octet_length('안녕하세요')
    -> , char_length('안녕하세요')
    -> , character_length('안녕하세요')
    -> , bit_length('안녕하세요')
    -> from dual;
+----------------------+----------------------------+---------------------------+--------------------------------+--------------------------+
| length('안녕하세요') | octet_length('안녕하세요') | char_length('안녕하세요') | character_length('안녕하세요') | bit_length('안녕하세요') |
+----------------------+----------------------------+---------------------------+--------------------------------+--------------------------+
|                   10 |                         10 |                        10 |                             10 |                       80 |
+----------------------+----------------------------+---------------------------+--------------------------------+--------------------------+
1 row in set (0.00 sec)

* 외부 클라이언트 툴로 입력할 경우 한글은 3byte

select length('안녕하세요')
, octet_length('안녕하세요')
, char_length('안녕하세요')
, character_length('안녕하세요')
, bit_length('안녕하세요')
from dual;

15 15 5 5 120

========================================================================

create table test
(name1 varchar(10)
,name2 nvarchar(10)
,name3 national varchar(10)
) engine=innodb;

drop table test;
delete from test;

# mysql 콘솔에서 직접 작업했을 경우

mysql> desc test;
+-------+-------------+------+-----+---------+-------+
| Field | Type        | Null | Key | Default | Extra |
+-------+-------------+------+-----+---------+-------+
| name1 | varchar(10) | YES  |     | NULL    |       |
| name2 | varchar(10) | YES  |     | NULL    |       |
| name3 | varchar(10) | YES  |     | NULL    |       |
+-------+-------------+------+-----+---------+-------+
3 rows in set (0.00 sec)


mysql> insert into test values('안녕하세요안녕하세요안녕하세요', '안녕하세요안녕하세요안녕하세요', '안녕하세요안녕하세요안녕하세요');
Query OK, 1 row affected, 3 warnings (0.00 sec)

mysql> insert into test values('hellohellohellohello', 'hellohellohellohello', 'hellohellohellohello');
Query OK, 1 row affected, 3 warnings (0.00 sec)

mysql> select * from test;
+------------+------------+------------+
| name1      | name2      | name3      |
+------------+------------+------------+
| 안녕하세요 | 안녕하세요 | 안녕하세요 |
| hellohello | hellohello | hellohello |
+------------+------------+------------+
2 rows in set (0.00 sec)

mysql> select length(name1)
    -> , octet_length(name1)
    -> , char_length(name1)
    -> , character_length(name1)
    -> , bit_length(name1)
    -> from test;
+---------------+---------------------+--------------------+-------------------------+-------------------+
| length(name1) | octet_length(name1) | char_length(name1) | character_length(name1) | bit_length(name1) |
+---------------+---------------------+--------------------+-------------------------+-------------------+
|            20 |                  20 |                 10 |                      10 |               160 |
|            10 |                  10 |                 10 |                      10 |                80 |
+---------------+---------------------+--------------------+-------------------------+-------------------+
2 rows in set (0.00 sec)

# mysql 외부 클라이언트 소프트웨어로 작업한 경우

select * from test;

¾È³çÇϼ¼¿ä ¾È³çÇϼ¼¿ä ¾È³çÇϼ¼¿ä
hellohello hellohello hellohello

insert into test values('안녕하세요안녕하세요안녕하세요', '안녕하세요안녕하세요안녕하세요', '안녕하세요안녕하세요안녕하세요');
insert into test values('hellohellohellohello', 'hellohellohellohello', 'hellohellohellohello');

select * from test;

¾È³çÇϼ¼¿ä ¾È³çÇϼ¼¿ä ¾È³çÇϼ¼¿ä
hellohello hellohello hellohello
안녕하세요안녕하세요 안녕하세요안녕하세요 안녕하세요안녕하세요
hellohello hellohello hellohello

mysql> select length(name1)
    -> , octet_length(name1)
    -> , char_length(name1)
    -> , character_length(name1)
    -> , bit_length(name1)
    -> from test;
+---------------+---------------------+--------------------+-------------------------+-------------------+
| length(name1) | octet_length(name1) | char_length(name1) | character_length(name1) | bit_length(name1) |
+---------------+---------------------+--------------------+-------------------------+-------------------+
|            20 |                  20 |                 10 |                      10 |               160 |
|            10 |                  10 |                 10 |                      10 |                80 |
|            30 |                  30 |                 10 |                      10 |               240 |
|            10 |                  10 |                 10 |                      10 |                80 |
+---------------+---------------------+--------------------+-------------------------+-------------------+
4 rows in set (0.00 sec)