utf8mb4和utf8到底有什么區(qū)別呢？原來以往的mysql的utf8一個字符最多3字節(jié)，而utf8mb4則擴(kuò)展到一個字符最多能有4字節(jié)，所以能支持更多的字符集。
將Mysql的編碼從utf8轉(zhuǎn)換成utf8mb4。
需要 >= MySQL 5.5.3版本、從庫也必須是5.5的了、低版本不支持這個字符集、復(fù)制報錯
停止MySQL Server服務(wù)
修改 my.cnf或者mysql.ini
[client] default-character-set = utf8mb4 [mysql] default-character-set = utf8mb4 [mysqld] character-set-client-handshake = FALSE character-set-server = utf8mb4 collation-server = utf8mb4_unicode_ci init_connect='SET NAMES utf8mb4'
重啟 MySQL Server、檢查字符集。
查看服務(wù)器字符集設(shè)置
mysql> SHOW VARIABLES WHERE Variable_name LIKE 'character%' OR Variable_name LIKE 'collation%';
+--------------------------+--------------------+ | Variable_name | Value | +--------------------------+--------------------+ | character_set_client | utf8mb4 | | character_set_connection | utf8mb4 | | character_set_database | utf8mb4 | | character_set_filesystem | binary | | character_set_results | utf8mb4 | | character_set_server | utf8mb4 | | character_set_system | utf8 | | collation_connection | utf8mb4_unicode_ci | | collation_database | utf8mb4_unicode_ci | | collation_server | utf8mb4_unicode_ci | +--------------------------+--------------------+
查看數(shù)據(jù)庫字符集
mysql> select * from SCHEMATA where SCHEMA_NAME='ttlsa';
+--------------+-------------+----------------------------+------------------------+----------+ | CATALOG_NAME | SCHEMA_NAME | DEFAULT_CHARACTER_SET_NAME | DEFAULT_COLLATION_NAME | SQL_PATH | +--------------+-------------+----------------------------+------------------------+----------+ | def | ttlsa | utf8mb4 | utf8mb4_unicode_ci | NULL | +--------------+-------------+----------------------------+------------------------+----------+
查看表字符集
mysql> select TABLE_SCHEMA,TABLE_NAME,TABLE_COLLATION from information_schema.TABLES;
+--------------------+----------------------------------------------------+--------------------+ | TABLE_SCHEMA | TABLE_NAME | TABLE_COLLATION | +--------------------+----------------------------------------------------+--------------------+
查看列字符集
mysql> select TABLE_SCHEMA,TABLE_NAME,COLUMN_NAME,COLLATION_NAME from COLUMNS;
+--------------------+----------------------------------------------------+--------------------------------------------+--------------------+ | TABLE_SCHEMA | TABLE_NAME | COLUMN_NAME | COLLATION_NAME | +--------------------+----------------------------------------------------+--------------------------------------------+--------------------+
轉(zhuǎn)換字符集語句
use information_schema;
SELECT concat("ALTER DATABASE `",table_schema,"` CHARACTER SET = utf8mb4 COLLATE = utf8mb4_unicode_ci;") as _sql
FROM `TABLES` where table_schema like "DB_NAME" group by table_schema;
SELECT concat("ALTER TABLE `",table_schema,"`.`",table_name,"` CONVERT TO CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci;") as _sql
FROM `TABLES` where table_schema like "DB_NAME" group by table_schema, table_name;
SELECT concat("ALTER TABLE `",table_schema,"`.`",table_name, "` CHANGE `",column_name,"` `",column_name,"` ",data_type,"(",character_maximum_length,") CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci;") as _sql
FROM `COLUMNS` where table_schema like "DB_NAME" and data_type in ('varchar');
SELECT concat("ALTER TABLE `",table_schema,"`.`",table_name, "` CHANGE `",column_name,"` `",column_name,"` ",data_type," CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci;") as _sql
FROM `COLUMNS` where table_schema like "DB_NAME" and data_type in ('text','tinytext','mediumtext','long聲明：本網(wǎng)頁內(nèi)容旨在傳播知識，若有侵權(quán)等問題請及時與本網(wǎng)聯(lián)系，我們將在第一時間刪除處理。TEL:177 7030 7066 E-MAIL:11247931@qq.com
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