# 修改数据库:
ALTER DATABASE database_name CHARACTER SET = utf8mb4 COLLATE = utf8mb4_unicode_ci;
# 修改表:
ALTER TABLE table_name CONVERT TO CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci;
# 修改表字段:
ALTER TABLE table_name CHANGE column_name column_name VARCHAR(191) CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci;  

[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'  

mysql> SHOW VARIABLES WHERE Variable_name LIKE 'character\_set\_%' 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 |
+--------------------------+--------------------+

mysql> SHOW FULL FIELDS FROM tbl_user;

    /**把用户输入的文本转义（主要针对特殊符号和emoji表情）*/public function userTextEncode($str){if(!is_string($str))return $str;if(!$str || $str=='undefined')return '';$text = json_encode($str); //暴露出unicode$text = preg_replace_callback("/(\\\u[ed][0-9a-f]{3})/i",function($str){return addslashes($str[0]);},$text);//将emoji的unicode留下，其他不动，这里的正则比原答案增加了d，因为我发现我很多emoji实际上是\ud开头的，反而暂时没发现有\ue开头。return json_decode($text);}/**解码上面的转义*/public function userTextDecode($str){$text = json_encode($str); //暴露出unicode$text = preg_replace_callback('/\\\\\\\\/i',function($str){return '\\';},$text); //将两条斜杠变成一条，其他不动return json_decode($text);}