修改mysql-GROUP_CONCAT最大长度

GROUP_CONCAT()函数可以将多条记录的同一字段的值，拼接成一条记录返回。但是默认情况下，这个拼接最大长度是有限制的，导致结果不完整。

可以使用sql查询最大长度： show variables like 'group_concat_max_len';

修改最大长度：

SET GLOBAL group_concat_max_len = 4294967295;
SET SESSION group_concat_max_len = 4294967295;

修改sql_mode使得分组查询可以多group返回值

1. 查询
   1. SELECT @@sql_mode;
2. 修改
   1. SET @@global.sql_mode ='STRICT_TRANS_TABLES,NO_ZERO_IN_DATE,NO_ZERO_DATE,ERROR_FOR_DIVISION_BY_ZERO,NO_ENGINE_SUBSTITUTION';
3. 对于已存在的修改
   1. SET sql_mode ='STRICT_TRANS_TABLES,NO_ZERO_IN_DATE,NO_ZERO_DATE,ERROR_FOR_DIVISION_BY_ZERO,NO_ENGINE_SUBSTITUTION';

mysql允许root 用户远程登录

1.查看用户

SELECT User, Host FROM user;

2.授权

GRANT ALL PRIVILEGES ON *.* TO 'root'@'%' IDENTIFIED BY 'Yps!12340101' WITH GRANT OPTION; GRANT ALL PRIVILEGES ON *.* TO 'root'@'%'  IDENTIFIED BY 'Yps!12340101' WITH GRANT OPTION;

8.0.25

CREATE USER 'root@%' IDENTIFIED BY 'PAN1987ding1217.’

CREATE USER 'db_question' IDENTIFIED BY 'db_question'

grant all privileges on *.* to 'root'@'%' with grant option;

grant all privileges on *.* to 'db_question'@'%' with grant option;


ALTER USER 'root'@'%' IDENTIFIED WITH mysql_native_password BY 'PAN1987ding1217.’;

ALTER USER 'db_question'@'%' IDENTIFIED WITH mysql_native_password BY 'db_question.';

ALTER USER 'cc_qljs_admin'@'%' IDENTIFIED WITH mysql_native_password BY 'CC_qljs_pass';

grant all privileges on cc_qljs_db.* to 'cc_qljs_admin'@'%' with grant option;