Copy existing table schema to a new table
Answer:
To copy the table schema of an existing table to a new table, without copying its data:
mysql> CREATE TABLE new_table LIKE old_table;
Feb 152010
Feb 142010
Turn off InnoDB support in MySQL
Answer:
If you never use the InnoDB storage engine in MySQL, it is better to disable it.
To disable this feature, edit the MySQL configurations, e.g. /etc/my.cnf
[mysqld]
...
...
skip-innodb
Add the "skip-innodb" will do the tricks for you.
Don't forget to restart MySQL to take effect.
# /sbin/service mysqld restart
Feb 062010
Reset MySQL root password
Answer:
If you have forgotten the MySQL root password, follow the steps below to reset the root password (for Ubuntu/Debian).
1. Shutdown MySQL
# /etc/init.d/mysql stop
2. Startup MySQL using command without grant tables, take the process to run in background
# /usr/bin/mysqld_safe --skip-grant-tables &
3. Login into the MySQL database
# mysql --user=root mysql
4. Reset password
mysql>update user set Password=PASSWORD('newpassword') WHERE User='root';
Query OK, 2 rows affected (0.03 sec)
Rows matched: 2 Changed: 2 Warnings: 0
mysql>flush privileges;
Query OK, 0 rows affected (0.02 sec)
5. Shutdown MySQL
Bring the MySQL server process to foreground now and kill it by Ctrl-C
# fg
[Ctrl-C]
6. Start MySQL using normal way
# /etc/init.d/mysql start
That's all.
Feb 062010
Show all MySQL supported character sets
Answer:
Execute the following command in the MySQL's shell.
mysql> SHOW CHARACTER SET
+----------+-----------------------------+---------------------+--------+
| Charset | Description | Default collation | Maxlen |
+----------+-----------------------------+---------------------+--------+
| big5 | Big5 Traditional Chinese | big5_chinese_ci | 2 |
| dec8 | DEC West European | dec8_swedish_ci | 1 |
| cp850 | DOS West European | cp850_general_ci | 1 |
| hp8 | HP West European | hp8_english_ci | 1 |
| koi8r | KOI8-R Relcom Russian | koi8r_general_ci | 1 |
| latin1 | cp1252 West European | latin1_swedish_ci | 1 |
| latin2 | ISO 8859-2 Central European | latin2_general_ci | 1 |
| swe7 | 7bit Swedish | swe7_swedish_ci | 1 |
| ascii | US ASCII | ascii_general_ci | 1 |
| ujis | EUC-JP Japanese | ujis_japanese_ci | 3 |
| sjis | Shift-JIS Japanese | sjis_japanese_ci | 2 |
| hebrew | ISO 8859-8 Hebrew | hebrew_general_ci | 1 |
| tis620 | TIS620 Thai | tis620_thai_ci | 1 |
| euckr | EUC-KR Korean | euckr_korean_ci | 2 |
| koi8u | KOI8-U Ukrainian | koi8u_general_ci | 1 |
| gb2312 | GB2312 Simplified Chinese | gb2312_chinese_ci | 2 |
| greek | ISO 8859-7 Greek | greek_general_ci | 1 |
| cp1250 | Windows Central European | cp1250_general_ci | 1 |
| gbk | GBK Simplified Chinese | gbk_chinese_ci | 2 |
| latin5 | ISO 8859-9 Turkish | latin5_turkish_ci | 1 |
| armscii8 | ARMSCII-8 Armenian | armscii8_general_ci | 1 |
| utf8 | UTF-8 Unicode | utf8_general_ci | 3 |
| ucs2 | UCS-2 Unicode | ucs2_general_ci | 2 |
| cp866 | DOS Russian | cp866_general_ci | 1 |
| keybcs2 | DOS Kamenicky Czech-Slovak | keybcs2_general_ci | 1 |
| macce | Mac Central European | macce_general_ci | 1 |
| macroman | Mac West European | macroman_general_ci | 1 |
| cp852 | DOS Central European | cp852_general_ci | 1 |
| latin7 | ISO 8859-13 Baltic | latin7_general_ci | 1 |
| cp1251 | Windows Cyrillic | cp1251_general_ci | 1 |
| cp1256 | Windows Arabic | cp1256_general_ci | 1 |
| cp1257 | Windows Baltic | cp1257_general_ci | 1 |
| binary | Binary pseudo charset | binary | 1 |
| geostd8 | GEOSTD8 Georgian | geostd8_general_ci | 1 |
| cp932 | SJIS for Windows Japanese | cp932_japanese_ci | 2 |
| eucjpms | UJIS for Windows Japanese | eucjpms_japanese_ci | 3 |
+----------+-----------------------------+---------------------+--------+
36 rows in set (0.00 sec)
Feb 012010
Export only a subset of table using mysqldump
Answer:
Dump a subset of table is possible with mysqldump
E.g.
# mysqldump my_db my_table -w"id>10"
The above command will dump all the rows in the table "my_table", where the field id is greater than 10.
