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Mysql Add Column Default Value

Mysql Add Column Default Value is used to add the default value to the column. The records take a default value when there is no value for a records put inside the specified column of table.

Understand with Example

The Tutorial illustrate an example from 'Mysql Add Column Default Value'. To understand and grasp this example we create a table 'stu' and 'lib' with required fieldnames and datatypes respectively.

Create Table Stu

Create Table Stu(Id int, Name varchar(10), Class  int);

Describe Stu

The Describe Stu is used to describe the fieldname,Type,Null ,etc in the table.

+-------+-------------+------+-----+---------+-------+
| Field | Type        | Null | Key | Default | Extra |
+-------+-------------+------+-----+---------+-------+
| Id    | int(11)     | YES  |     |         |       |
| Name  | varchar(10) | YES  |     |         |       |
| Class | int(11)     | YES  |     |         |       |
+-------+-------------+------+-----+---------+-------+

Query for Add Column Default Value

The Query Alter is used to modify the table 'stu' and add a default value of 10 for those records which don't have value specified in a column.

ALTER TABLE Stu MODIFY class int Default '10';

Describe Stu

+-------+-------------+------+-----+---------+-------+
| Field | Type        | Null | Key | Default | Extra |
+-------+-------------+------+-----+---------+-------+
| Id    | int(11)     | YES  |     |         |       |
| Name  | varchar(15) | YES  |     |         |       |
| class | int(11)     | YES  |     | 10      |       |
+-------+-------------+------+-----+---------+-------+

Insert data into Stu

Insert Into Stu (Id, Name) values(1,'Komal');
Insert Into Stu (Id, Name) values(2,'Ajay');
Insert Into Stu (Id, Name) values(3,'Rakesh');
Insert Into Stu (Id, Name) values(4,'Bhanu');
Insert Into Stu (Id, Name) values(5,'Santosh');

Stu Table

+------+---------+-------+
| Id   | Name    | class |
+------+---------+-------+
| 1    | Komal   | 10    |
| 2    | Ajay    | 10    |
| 3    | Rakesh  | 10    |
| 4    | Bhanu   | 10    |
| 5    | Santosh | 10    |
+------+---------+-------+

Mysql Add Column Default Value

Mysql Add Column Default Value

Mysql Add Column Default Value

Tutorials