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 |
+------+---------+-------+
|
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