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ERROR 1045 (28000): Access denied for user 'root'@'localhost' (using password: YES)

linux 利用yum源安装mysql client 5.7

mysql查询当前数据库下的表名。

复制用户复制菜单

将表的所有列名拼接成字符串

将表的所有列明拼接成字符串

error code 1235

CAST() 和 CONVERT() 函数均可将 varcahr 转 int 。

将菜单树的所有根节点（parent_id=0）的id拼接成字符串。sql 代码：执行结果：将菜单树的所有根节点（parent_id=0）的id拼接成字符串。sql 代码：换个分隔符执行结果：

DELETE u FROM sys_user u LEFT JOIN sys_dept d ON u.dept_id=d.dept_id WHERE d.dept_id=102 and u.user_id!=1;DELETE ur FROM sys_user_role ur LEFT JOIN sys_user u ON ur.user_id=u.user_idWHERE u.user_id is null;

前言使用database-dictionary项目完成自动生成数据字典Giteehttps://gitee.com/cdtrh_group/database-dictionary安装可以通过docker安装。docker run -itd -p 9998:9998 --name=database-dictionary 251878350/database-dictionary:v4.4生成数据字典在上图中填写完信息后，点击“连接”按钮后即生成文档。数据库文档为html格式（Markd

REPLACE字符串替换函数REPLACE(str,from_str,to_str) 示例：select REPLACE('123abcd89', 'abcd', '4567');输出结果：123456789处理历史稿件中的图片路径update `article` set content=REPLACE(content, 'http://localhost/static/image/', 'http://www.mydomain.com/static/image/') where c

前言CentOS Linux release 7.6.1810mysql 5.7.31下载rpm需要下载下面这三个rpm：mysql-community-common-5.7.31-1.el7.x86_64.rpmmysql-community-libs-5.7.31-1.el7.x86_64.rpmmysql-community-client-5.7.31-1.el7.x86_64.rpmwget https://cdn.mysql.com/archives/mysql-5.7/m

错误shell> yum install -y mysql-community-common-5.7.31-1.el7.x86_64.rpm发生错误：file /usr/share/mysql/czech/errmsg.sys from install of mysql-community-common-5.7.31-1.el7.x86_64 conflicts with file from package mysql-libs-5.5.68-1.el7.x86_64错误原因检查发现，该

目录前言java md5+base64java md5+base64：commons-codecjava md5+base64：shiro-corejava covertToString(md5)+base64java covertToString(md5)+base64：commons-codecmysql md5+base64前言jdk1.8mysql 5.7java md5+base64import java.io.UnsupportedEncodingException;import

UPDATE table_1 t1 LEFT JOIN table_2 t2 on t2.t1_id = t1.id SET t1.t2_name = t2.name, t1.t2_age=t2.agewhere t1.t1_id is not null;

目录前言HEXHEX 函数的参数为数字时HEX 函数的参数为字符串时UNHEXHEX 转化 binary 类型前言mysql 5.7.31HEXHEX 函数的官方说明如下：HEX(str), HEX(N)For a string argument str, HEX() returns a hexadecimal string representation of str where each byte of each character in str is converted to two

前言mysql 5.7.31base64编码mysql> select to_base64("123");select to_base64("123");+------------------+| to_base64("123") |+------------------+| MTIz |+------------------+1 row in set (0.01 sec)base64解码mysql> select from_base64("

前言mysql 5.7.31md5函数加密mysql> select md5('');+----------------------------------+| md5('') |+----------------------------------+| d41d8cd98f00b204e9800998ecf8427e |+----------------------------------+1 row in set (0.02

前言mysql 5.7.31jdk 1.8mysql的时区假设有个java应用，通过jdbc连接mysql，而mysql安装在linux上，此时有哪些时区？linux有个时区mysql有个时区jdbc有个时区java应用所在的jvm有个时区上面几个时区中，能够影响mysql中数据的有2个时区：mysql有个时区（设置方法：mysql 时区设置）jdbc有个时区（设置方法：网上搜索）jdbc时区当java对象类型是Date类型，mysql字段类型为datetime、tim

前言mysql 5.7.31jdk 1.8查看默认时区mysql> show variables like '%time_zone%';+------------------+--------+| Variable_name | Value |+------------------+--------+| system_time_zone | UTC || time_zone | SYSTEM |+------------------+--------

jdbc urljdbc:mysql://59.110.137.112:3306/answer?useUnicode=true&characterEncoding=utf8&zeroDateTimeBehavior=convertToNull&useSSL=true&serverTimezone=GMT%2B8&nullCatalogMeansCurrent=true设置时区设置时区时，添加serverTimezone参数，比如serverTimezone

前言CentOS 7.9Docker Version: 1.13.1准备docker 已安装。选择合适的mysql镜像(mysql:5.7.31)。拉取镜像shell> docker pull mysql:5.7.31Trying to pull repository docker.io/library/mysql ... 5.7.31: Pulling from docker.io/library/mysqlbb79b6b2107f: Pull complete

前言mysql 5.7.31centos 7.0默认情况下，mysql帐号不允许从远程登陆，只能在localhost登录。在开发环境中，允许任意ip可以连接数据库。生成环境中，应使用白名单方式，指定允许的ip。登陆mysql数据库 mysql -u root -p查看user表mysql> use mysql;Database changedmysql> select host,user,authentication_stringfrom user;+------

前言mysql 5.7.31增减一小时date_sub(NOW(), interval -1 hour)date_sub(NOW(), interval 1 hour)增减一天：date_sub(NOW(), interval -1 day)date_sub(NOW(), interval 1 day)增减一月：date_sub(NOW(), interval -1 month)date_sub(NOW(), interval 1 month)增减一季度：date_s

前言mysql 5.7.31思路将日期格式化得到字符串将字符串转换成date类型（此步根据实际情况决定是否需要）当年SELECT @year := date_format(now(), '%Y0101'); /* 将日期格式化，得到当年字符串 */SELECT str_to_date(@year, '%Y%m%d'); /* 将字符串转换成date类型 */SELECT str_to_date(date_format(now(), '%Y0101'), '%Y%m%d'); /*

前言mysql 5.7建表语句的自增列CREATE TABLE `shop_open_apply` ( `id` bigint(20) unsigned NOT NULL AUTO_INCREMENT COMMENT 'id', PRIMARY KEY (`id`)) ENGINE=InnoDB AUTO_INCREMENT=1 DEFAULT CHARSET=utf8 COMMENT='店铺申请表'查看自增列的值select AUTO_INCREMENT from INFORMA

我有一个表，如下：我需要要重置祖级字段

前言mysql 5.7.31字符串转化为日期类型SELECT str_to_date('2021-05-07', '%Y-%m-%d'); /*2021-05-07*/SELECT str_to_date('2021-05-07 23:00:00', '%Y-%m-%d %H:%i:%s'); /*2021-05-07 23:00:00*/SELECT str_to_date('2021-05-07 11:00:00 PM', '%Y-%m-%d %h:%i:%s %p'); /*2021-0