本篇文章记录了Mysql数据库的一些常规操作指令,便于使用数据库时查找。
col_name
列名称 tbl_name
表名称 operator
运算符 val
值 col
列 db_name
数据库名称 col_attr
数据类型 file_loc
文件位置
1.获取数据:
select col_name from tbl_name;
select * from tbl_name;//匹配所有列
select distinct col_name from tbl_name;//仅返回不同值
2.获取满足特定条件的数据:
select col_name from tbl_name where col 运算符 值;
例子:
select * from orders where id = 3;
select * from orders where id = 3 or id = 4;
select * from orders where name like 'N%';//选取制定模式
select * from orders where 1 between 3;//选取两值之间的数据
3.对数据进行排序:
select col from tbl_name order by col asc;//生序排列
select col from tbl_name order by col desc;//降序排列
4.插入数据:
insert into tbl_name values(val1,val2,...);
insert into tbl_name(col1,col2,...) values(val1,val2,...);//插入指定列
5.修改数据:
update tbl_name set col_name = val1 where col = val2;
6.删除数据:
delete from tbl_name where col = val;
7.规定返回数据数目:
select col_name from tbl_name limit val;
```select top 50 percent * from tbl_name;//选取50%的记录```
8.创建数据:
```create database db_name;//创建数据库```
```create table tbl_name(col1 attr1,col2 attr2,....);```
9.撤销表:
```drop table tbl_name;```
```drop database db_name;```
```truncate table tbl_name;//仅删除表格中数据
10.alter已有表添加、删除、修改:
```alter table tbl_name add column col_name col_attr;```
```alter table tbl_name drop column col_name col_attr;```
```alter table tbl_name alter column col_name col_attr;```
11.备份复件:
```select col_name into tbl1 from tbl2;```
12.字段编码格式改变:
例子:
```alter table tbl_name modify col_name col_attr character set gbk;//改为gbk编码模式```
13.查看数据:
```show full columns from tbl_name;//查看表单字符集设置```
```show tables;//查看所在数据库所有表单```
```show databases;```
```describe tbl_name;//查看表单详细信息```
14.导入文件:
```source file_loc;//导入外部sql文件```
例子:
```source D:\bookmark.sql;```
```load data local infile 'file_loc' into table tbl_name;//txt格式文件导入数据库```
例子:
```load data local infile 'D:\excel.txt' into table tbl_name character set utf8 fields terminated by',';```