Chapter VI operational data

Create a data table

CREATE TABLE table names (column names an attribute, second attribute column names ...);

View table structure

SHOW [FULL] COLUMNS FROM database name [FROM database name];

Use DESCRIBE ranked database name;

Modify table structure

ALTER [INGNORE] TABLE database name alter_spec [, alter_spec] ... | table_options

Add new fields and modify field definitions

ALTER TABLE td_admin ADD email varchar(50) not null,modify user varchar(40);

Modify field name

ALTER TABLE db_admin.tb_usernew1 CHANGE COLUMN user username VARCHAR(30) NULL DEFAULT NULL;

Delete field

ALTER TABLE tb_admin DROP email;

Modify the table name

ALTER TABLE tb_usernew1 RENAME AS tb_userOld;

Rename Table

RENAME TABLE tb_admin TO tb_user;

Copy the table

CREATE TABLE [IF NOT EXISTS] Table Name

{LIKE Data Source Table Name | (the LIKE source data table name)}

When you copy a table, at the same time you want to copy its contents:

CREATE TABLE tb_userNew1

　　AS SELECT * FROM tb_user;

Delete table

DROP TABLE [IF EXISTS] data table;