MySQL character set garbled characters and solutions

mysql> show variables like 'character_set%';
+--------------------------+----------------------------------+
| Variable_name | Value |
+--------------------------+----------------------------------+
| character_set_client | utf8 |
| character_set_connection | utf8 |
| character_set_database | utf8 |
| character_set_filesystem | binary |
| character_set_results | utf8 |
| character_set_server | utf8 |
| character_set_system | utf8 |
| character_sets_dir | /usr/local/mysql/share/charsets/ |
+--------------------------+----------------------------------+
8 rows in set (0.00 sec)
 
mysql> insert into test.table10 values ​​(1,'云中鹤');
Query OK, 1 row affected (0.00 sec)
 
mysql> select * from test.table10;
+------+-----------+
| id | names |
+------+-----------+
| 1 | Crane in the Clouds|
+------+-----------+
1 row in set (0.00 sec)
 
mysql> set names latin1;
Query OK, 0 rows affected (0.00 sec)
 
mysql> select * from test.table10;
+------+-------+
| id | names |
+------+-------+
| 1 | ??? |
+------+-------+
1 row in set (0.00 sec)
 
mysql> show variables like 'character_set%';
+--------------------------+----------------------------------+
| Variable_name | Value |
+--------------------------+----------------------------------+
| character_set_client | latin1 #Character set used by client source data | character_set_connection | latin1 #Connection layer character set | character_set_database | utf8 #Default character set of currently selected database | character_set_filesystem | binary   
| character_set_results | latin1 #query result character set |
| character_set_server | utf8 #Default internal operation character set |
| character_set_system | utf8 #system metadata (field names, etc.) character set | character_sets_dir | /usr/local/mysql/share/charsets/ |
+--------------------------+----------------------------------+
8 rows in set (0.00 sec)

 mysql> set names utf8;
 Query OK, 0 rows affected (0.01 sec)

 [root@node1 ~]# mysql -S /tmp/mysql.sock4 --defaults-character-set=utf8 #-S specifies the socket file for multiple instances of mysql.
 Use --defaults-character-set to specify the default character set.

 vim /etc/sysconfig/i18n
 LANG='zh_CN.UTF-8' #If my.cnf is not specified, the system character set is used by default

  [client]
  default-character-set=latin1

  [mysql]
  default-character-set=latin1

mysql> show variables like 'character_set%';#I changed it to utf8, so the three parameters of the client are all utf8. You can set the character set yourself.
+--------------------------+----------------------------------+
| Variable_name | Value |
+--------------------------+----------------------------------+
| character_set_client | utf8 |
| character_set_connection | utf8 |
| character_set_database | utf8 |
| character_set_filesystem | binary |
| character_set_results | utf8 |
| character_set_server | utf8 |
| character_set_system | utf8 |
| character_sets_dir | /usr/local/mysql/share/charsets/ |

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 | #common | 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 | #Common | 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 |#Common | 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 |
| utf8mb4 | UTF-8 Unicode | utf8mb4_general_ci | 4 | #Common | cp1251 | Windows Cyrillic | cp1251_general_ci | 1 |
| utf16 | UTF-16 Unicode | utf16_general_ci | 4 |
| cp1256 | Windows Arabic | cp1256_general_ci | 1 |
| cp1257 | Windows Baltic | cp1257_general_ci | 1 |
| utf32 | UTF-32 Unicode | utf32_general_ci | 4 |
| 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 |
+----------+-----------------------------+---------------------+--------+
39 rows in set (0.00 sec)

[mysqld]
...
character-set-server=utf8 #Add this statement to set the server-side character set.

| character_set_server | utf8 
| character_set_database | utf8

alter database dbname character set xxx; #It is only valid for future data and invalid for previous data. Basically not used

mysqldump -S /tmp/mysql.sock4 --default-character-set=utf8 -d test > /data/test-`date +%F`.sql #1. Export the table structure without exporting data vim /data/test-`date +%F`.sql
DROP TABLE IF EXISTS `table10`;
/*!40101 SET @saved_cs_client = @@character_set_client */;
/*!40101 SET character_set_client = utf8 */;
CREATE TABLE `table10` (
 `id` int(11) DEFAULT NULL,
 `names` char(20) DEFAULT NULL
) ENGINE=InnoDB DEFAULT CHARSET=utf8; #2. Change the CHARSET here to the character set you want to modifymysqldump -S /tmp/mysql.sock4 --extended-insert --no-create-info test > /data/test-data-`date +%F`.sql #3. Export data contentvim /data/test-data-`date +%F`.sql
LOCK TABLES `table10` WRITE;
set names utf8; #4, this line is added, specify the character set you want to convert INSERT INTO `table10` VALUES (1,'云中鹤');
UNLOCK TABLES;

mysql> create database if not exists test; #5. Create a database to store the converted data Query OK, 1 row affected, 0 warning (0.00 sec)

mysql -S /tmp/mysql.sock4 test < /data/test-`date +%F`.sql #6. Import table structuremysql -S /tmp/mysql.sock4 test < /data/test-data-2015-09-25.sql #7. Import table data