mysql alter table add column

original varchar (25) to varchar (20) Modify Field name The Code is as follows: Mysql> alter table person change stu_name name varchar (25 ); Query OK, 0 rows affected (0.20 sec) Records: 0 Duplicates: 0 Warnings: 0 Stu_name is the original name and name is the new name. It should be noted that no matter whether the data type is changed, the subsequent data

The ALTER TABLE statement is used to add, modify, or delete a column's original table in an existing table:first, Alter adds a new column to the table syntax:ALTER

/* CREATE TABLE and set PRIMARY key */creation table table_user ( user_id INT IDENTITY () not NULL, user_name NVARCHAR (max) not NULL, last_updated_by NVARCHAR (last_updated_date), DATETIME, CONSTRAINT user_pk PRIMARY KEY (user_id) ); /*alter table adds multiple fields */

Mysql adds a column, deletes a column, modifies a column name, and mysql columns at a certain position in the table. To add a column to a c

test where ID mysql> TRUNCATE TABLE test; #删除allMysql> select * from test;Empty Set (0.00 sec) On top, modify the table name in the database, add and remove fields from the table. mysql> Use GBK #进入gbk数据库

The MySQL ALTER TABLE statement can modify the basic structure of the table, such as adding fields, deleting fields, adding primary keys, adding indexes, modifying field data types, renaming tables, and so on, and this article introduces the use of MySQL

Alter table only allows adding columns that can contain null values or specified the default definition. If: If exists (select 1 from sysobjects where name = n' tab _ test') and not exists (select 1 from sysobjects A, syscolumns B where B. id =. ID and B. name = n' Col _ test' and. name = n' tab _ test ')Alter table ta

Alter is a very powerful feature. We can use ALTER to modify the data table name and some other operations, and let's look at an example of adding, deleting, and modifying the table name in the ALTER datasheet in MySQL. Modify

Label:Get ready:CREATE table t (x int,y int);　　Usage 1:Modifying a column's data classALTER TABLE t modify column y nvarchar (32);　　Usage 2:Add a column to a tableALTER TABLE t add

type.Tips: we can also use change to achieve the modify effect. We only need to write the same field name after it.Add fields without integrity constraints Copy codeThe Code is as follows:Mysql> alter table person add sex boolean;Query OK, 0 rows affected (0.21 sec)Records: 0 Duplicates: 0 Warnings: 0 The sex here is followed by only the data type, without the i

ALTER TABLE changes the table to the current character set. If a duplicate key error is encountered during the execution of the ALTER TABLE operation, the new character set maps 2 keys to the same value or the table is corrupted.

The following articles mainly describe the information related to MySQL Alter Table function leakage. If you are using MySQL Alter Table, you can use the following articles to study it! Affected Systems: MySQLABMySQL5.1.x

The MySQL Replication encountered the following error message: (mysql> show slave status\g # simplified message below) last_errno:1580Last_error:error ' You cannot ' ALTER ' a log table if logging are enabled ' on query. Default database: ' MySQL '. Query: ' ALTERTABLE Slow

A collection of SQL statements for the ALTER TABLE of MySQL, including adding, modifying, deleting fields, renaming tables, adding, deleting primary keys, and so on. 1: Delete Column ALTER table "

SQL Server has a strange problem (2000/2005 all have this problem ): The mm_bjjhmx table has the ID of the auto-increment column of the primary key, and a column "sequence number" is also required ". Run the following statements: Select Identity (INT, 1, 1) XH, A. * into # TBFrom mm_bjjhmxWhere bjjhid = 4Order by A. bjbm, A. bjmc;Select * from # TBDrop

The following error is reported when I try to modify the primary key of the MySQL data table with Navicat to automatically grow1602 ALTER TABLE causes auto_increment resequencing, resulting in duplicate entry ' 1′for key ' PRIMARY 'Workaround:1th Step: Change the value of the primary key field to 0 for any number that

Add a class style to all cells in Column 2nd of the table;, Column 2nd of the table Add the background color red to the second column of a table