Query, add, delete, and modify Databases

Mysql does not take a long time to learn. database operations simply add records, search records, delete records, and modify records.
Summarize the following commands to share with you:
Connection command: mysql-h [host address]-u [user name]-p [User Password]
Create database: create database [database name]
Show all databases: show databases;
Open Database: use [database name]
Status of the currently selected DATABASE: select database ();
CREATE a data TABLE: create table [TABLE name] ([field name] [field type] ([field requirements]) [field parameters], ......);
Display the data table field: describe table name;
Current Database Data Table Structure: show tables;
Change table
Alter table [TABLE name] add column [field name] DATATYPE
Note: Add a column (the syntax of a column is not deleted.
Alter table [TABLE name] add primary key ([field name])
Note: You can change the table definition to set a column as a primary key.
Alter table [TABLE name] drop primary key ([field name])
Delete the definition of the primary key.
Show columns from tablename;
Delete database: drop database [database name];
Delete table: drop table [table name];
Data Operations
Add: insert into [Table name] VALUES ('','',... ordered data );
Query: SELECT * FROM [Table name] WHERE ([condition]);
Create index [INDEX file name] ON [Table name] ([field name]);
DELETE: delete from [Table name] WHERE ([condition]);
Modify: UPDATE [Table name] SET [Modification content such as name = 'Mary '] WHERE [condition];
Import external data text:
1. Execute External SQL scripts
Run mysql <input. SQL on the current database.
Run the following command on the specified database: mysql [Table name] <input. SQL
2. data Import command load data local infile "[file name]" into table [table name];
Back up the database: (under dos)
Mysqldump -- opt school> school. bbb