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SQL Alter Column Not Null

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The Column Not Null in SQL is used when you want the column should not be null in your table.

SQL Alter Column Not Null

     

The Column Not Null in SQL is used when you want the column should not be null in your table.

Understand with Example

The Tutorial express you a elaborative example on SQL Alter Column Not Null. The example create a Table Stu_Table is created using a create table. The insert into statement add  records or rows to the table 'Stu_Table'. The Describe Table  show you the table attribute like field name, data type, null etc. The created table have null values in field name. The 'Yes' null specify the field value can be empty or Optional.

Now  You want the specific data field value not to be empty. Once you define your field name not to be null, It is mandatory to insert the value into  specific field name. The Alter Table modify and change the table 'Stu_Table'. Modify keyword in SQL Query  modify the null value for the column 'Stu_Id' to not null. It is advisable for you to insert value into specified field.  

The Describe Table show you a modified field null value in table 'Stu_Table'.

Create Table Stu_Table

create table Stu_Table(Stu_Id varchar(2), Stu_Name varchar(10), 
Stu_Class  varchar(10))

Insert data into Stu_Table

insert into Stu_Table (Stu_Id, Stu_Name) values(1,'Komal');
insert into Stu_Table (Stu_Id, Stu_Name) values(2,'Ajay');
insert into Stu_Table (Stu_Id, Stu_Name) values(3,'Rakesh');
insert into Stu_Table (Stu_Id, Stu_Name) values(4,'Bhanu');
insert into Stu_Table (Stu_Id, Stu_Name) values(5,'Santosh');

Stu_Table

+--------+----------+-----------+
| Stu_Id | Stu_Name | Stu_Class |
+--------+----------+-----------+
| 1      | Komal    | 10        |
| 2      | Ajay     | 10        |
| 3      | Rakesh   | 10        |
| 4      | Bhanu    | 10        |
| 5      | Santosh  | 10        | 
+--------+----------+-----------+

Describe Stu_Table

+-----------+-------------+------+-----+---------+-------+
| Field     | Type        | Null | Key | Default | Extra |
+-----------+-------------+------+-----+---------+-------+
| Stu_Id    | varchar(2)  | YES  |     |         |       |
| Stu_Name  | varchar(10) | YES  |     |         |       |
| Stu_Class | varchar(10) | YES  |     |         |       |
+-----------+-------------+------+-----+---------+-------+

Alter column Not Null Query

ALTER TABLE Stu_Table MODIFY Stu_Id int(3)not null

Describe Stu_Table

+-----------+--------------+------+-----+---------+-------+
| Field     | Type         | Null | Key | Default | Extra |
+-----------+--------------+------+-----+---------+-------+
| Stu_Id    | int(3)       | No   |     |         |       |
| Stu_Name  | varchar(10)  | YES  |     |         |       |
| Stu_Class | varchar(10)  | YES  |     |         |       |
+-----------+--------------+------+-----+---------+-------+
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Posted on: December 20, 2008

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Comments:1
saurabh
February 14, 2013
error.need help.

Hi, I am getting an error near Modify keyword. i used the syntax in SQl query analyzer, but i am getting an error. Please help.
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