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How To Add a New Column to an Existing Table
How To Add a New Column to an Existing Table? - MySQL FAQs - Understanding SQL CREATE, ALTER and DROP Statements
✍: FYIcenter.com
If you have an existing table with existing data rows, and want to add a new column to that table, you can use the "ALTER TABLE ... ADD COLUMN" statement. The tutorial script below shows you a good example:
mysql> ALTER TABLE tip ADD COLUMN author VARCHAR(40); Query OK, 1 row affected (0.18 sec) Records: 1 Duplicates: 0 Warnings: 0 mysql> SHOW COLUMNS FROM tip; +-------------+--------------+------+-----+---------+------- | Field | Type | Null | Key | Default | Extra +-------------+--------------+------+-----+---------+------- | id | int(11) | NO | PRI | | | subject | varchar(80) | NO | | | | description | varchar(256) | NO | | | | create_date | date | YES | | NULL | | author | varchar(40) | YES | | NULL | +-------------+--------------+------+-----+---------+------- 5 rows in set (0.01 sec)
This SQL script added a new column called "author" to the "tip" table. NULL values were added to this column on all existing data rows.
2007-05-11, 4790👍, 0💬
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