How To Delete an Existing Column in a Table

Q

How To Delete an Existing Column in a Table? - MySQL FAQs - Understanding SQL CREATE, ALTER and DROP Statements

✍: FYIcenter.com

A

If you have an existing column in a table and you do not need that column any more, you can delete it with "ALTER TABLE ... DROP COLUMN" statement. Here is a tutorial script to delete an existing column:

mysql> ALTER TABLE tip DROP COLUMN create_date;
Query OK, 1 row affected (0.48 sec)
Records: 1  Duplicates: 0  Warnings: 0

mysql> SELECT * FROM tip;
+----+-------------+-------------------------+--------+
| id | subject     | description             | author |
+----+-------------+-------------------------+--------+
|  1 | Learn MySQL | Visit dev.fyicenter.com | NULL   |
+----+-------------+-------------------------+--------+
1 row in set (0.00 sec)

As you can see the column "create_date" is gone.

2007-05-11, 4556👍, 0💬

How To Create a Table Index
How To Create a Table Index? - MySQL FAQs - Understanding SQL CREATE, ALTER and DROP Statements If you have a table with a lots of rows, and you know that one of the columns will be used often as a search criteria, you can add an index for that column to improve the search performance. To add an ind... 2007-05-11, 4679👍, 0💬

How To See the CREATE TABLE Statement of an Existing Table
How To See the CREATE TABLE Statement of an Existing Table? - MySQL FAQs - Understanding SQL CREATE, ALTER and DROP Statements If you want to know how an existing table was created, you can use the "SHOW CREATE TABLE" command to get a copy of the "CREATE TABLE" statement back on an existing table. T... 2007-05-11, 4662👍, 0💬

How To Get a List of Indexes of an Existing Table
How To Get a List of Indexes of an Existing Table? - MySQL FAQs - Understanding SQL CREATE, ALTER and DROP Statements If you want to see the index you have just created for an existing table, you can use the "SHOW INDEX FROM tableName" command to get a list of all indexes in a given table. The tutor... 2007-05-11, 4644👍, 0💬

How To Create a New Table by Selecting Rows from Another Table
How To Create a New Table by Selecting Rows from Another Table? - MySQL FAQs - Understanding SQL CREATE, ALTER and DROP Statements Let's say you have a table with many data rows, now you want to create a backup copy of this table of all rows or a subset of them, you can use the "CREATE TABLE ... SEL... 2007-05-11, 4637👍, 0💬

How To Get a List of Columns in an Existing Table
How To Get a List of Columns in an Existing Table? - MySQL FAQs - Understanding SQL CREATE, ALTER and DROP Statements If you have an existing table, but you don't remember what are the columns used in the table, you can use the "SHOW COLUMNS FROM tableName" command to get a list of all columns of th... 2007-05-11, 4599👍, 0💬

How To Get a List of All Tables in a Database
How To Get a List of All Tables in a Database? - MySQL FAQs - Understanding SQL CREATE, ALTER and DROP Statements If you want to see the table you have just created, you can use the "SHOW TABLES" command to get a list of all tables in database. The tutorial script gives you a good example: mysql> SH... 2007-05-11, 4580👍, 0💬

How To Delete an Existing Column in a Table
How To Delete an Existing Column in a Table? - MySQL FAQs - Understanding SQL CREATE, ALTER and DROP Statements If you have an existing column in a table and you do not need that column any more, you can delete it with "ALTER TABLE ... DROP COLUMN" statement. Here is a tutorial script to delete an e... 2007-05-11, 4557👍, 0💬

How To Drop an Existing Table
How To Drop an Existing Table? - MySQL FAQs - Understanding SQL CREATE, ALTER and DROP Statements If you want to delete an existing table and its data rows, you can use the "DROP TABLE" statement as shown in the tutorial script below: mysql> SELECT * FROM tipBackup; +----+-------------+---------- ---... 2007-05-11, 4541👍, 0💬

How To Rename an Existing Column in a Table
How To Rename an Existing Column in a Table? - MySQL FAQs - Understanding SQL CREATE, ALTER and DROP Statements If you have an existing column in a table and you want to change the column name, you can use the "ALTER TABLE ... CHANGE" statement. This statement allows you to change the name of a colu... 2007-05-11, 4514👍, 0💬

All rights in the contents of this web site are reserved by the individual author. fyicenter.com does not guarantee the truthfulness, accuracy, or reliability of any contents.