#查看数据库物理存放目录
show variables like "%datadir%";
#查看所有数据库
show databases
#选择数据库
use your_db_name
#查看数据库表结构(需要先选择数据库【use your_db_name】)
describe your_table_name
#方法一：获取某个数据库的所有表的名字
SELECT table_name FROM information_schema.tables WHERE table_schema = 'your_db_name' AND table_type = 'base table'
#方法二：获取某个数据库的所有表的名字(需要先选择数据库【use your_db_name】)
show tables
#获取所有表的所有字段名
select table_name,column_name from information_schema.columns order by table_schema,table_name;
#获取表的所有字段名
select COLUMN_NAME from information_schema.COLUMNS where table_name = ‘your_table_name’ and table_schema = ‘your_db_name’;
#查看数据库所有索引
SELECT * FROM mysql.`innodb_index_stats` a WHERE a.`database_name` = 'your_db_name';
#查看某一表索引
SELECT * FROM mysql.`innodb_index_stats` a WHERE a.`database_name` = 'your_db_name' and a.table_name = 'your_table_name';
#查看某一表索引(需要先选择数据库【use mydatabyour_db_namesename】)
show index from your_table_name
#
SET FOREIGN_KEY_CHECKS = 0;
#查看开关状态
show variables like 'SQL_SAFE_UPDATES';
#修改下数据库模式
SET SQL_SAFE_UPDATES = 0;
#复制列
update demo_db.user_info set r=remark where id>0
#替换字符串
update user_info set r=replace(r,'http://www.xxx.com/','') where id>0;
update user_info set r=replace(r,'.html','') where id>0;
#是数字的列
SELECT book_id FROM books WHERE book_id REGEXP '[0-9]{1,}' limit 10000;
#不是数字的列
SELECT book_id FROM books WHERE book_id REGEXP '[0-9]{1,}'=0 limit 10000;
#查看当前连接情况
show processlist;
select * from information_schema.processlist;
# 记录存在则更新，不存在则插入
INSERT INTO testTabe (c1,c2,c3) VALUES (1,'insert c2','insert c3') ON DUPLICATE KEY UPDATE c2='update c2',c3='update c3';
#导入本地csv文件（摘自：https://blog.csdn.net/quiet_girl/article/details/71436108）
LOAD DATA LOCAL INFILE 'E:\DB\data.csv'
into table your_db_name.your_table_name
fields terminated by ',' optionally enclosed by '"' escaped by '"'
lines terminated by '
';
#导入本地csv文件（摘自：https://www.cnblogs.com/ahudyan-forever/p/5817847.html）
LOAD DATA LOCAL INFILE 'E:\DB\data.csv'
INTO TABLE `your_db_name`.`your_table_name`
FIELDS ESCAPED BY '\'
TERMINATED BY ','
ENCLOSED BY '"'
LINES TERMINATED BY '
'
(`AREA_NAME`, `AREA_CODE`, `CITY_ID`, `PROVINCE_NAME`, `PROVINCE_CODE`)