Mysql Alter Data Type
Mysql Alter Date Type is used to modify or change the Column datatype
in a table.
Understand with Example
The Tutorial cover an example on 'Mysql Alter Date Type'.To understand this
example we create a table 'userform' with required fieldname and datatype
respectively.The table 'userform' has a ID as Primary Key.
Create a table "userform"
CREATE TABLE `userform` (
`ID` int(11) NOT NULL auto_increment,
`username` varchar(100) default NULL,
`fname` varchar(100) default NULL,
`email` varchar(100) default NULL,
`contact` bigint(20) default NULL,
PRIMARY KEY (`ID`)
) |
Describe userform:
The Describe userform is used to describe the table
field,Null,Key,Default etc.
+----------+--------------+------+-----+---------+----------------+
| Field | Type | Null | Key | Default | Extra |
+----------+--------------+------+-----+---------+----------------+
| ID | int(11) | NO | PRI | | auto_increment |
| username | varchar(100) | YES | | | |
| fname | varchar(100) | YES | | | |
| email | varchar(100) | YES | | | |
| contact | bigint(20) | YES | | | | |
Select the record from table "userform":
+----+----------+---------+----------------------+---------+
| ID | username | fname | email | contact |
+----+----------+---------+----------------------+---------+
| 1 | vineet | vineet | vineet@roseindia.net | 12345 |
| 2 | sourabh | Sourabh | srbh@roseindia.net | 12345 |
+----+----------+---------+----------------------+---------+ |
Query to Alter Table "userform":
The Query Alter is used to modify the Table "userform" and
change the column datatype from "contact(
bigint)" to contact(varchar(130).
alter table userform change contact contact varchar(130);
|
+----------+--------------+------+-----+---------+----------------+
| Field | Type | Null | Key | Default | Extra |
+----------+--------------+------+-----+---------+----------------+
| ID | int(11) | NO | PRI | | auto_increment |
| username | varchar(100) | YES | | | |
| fname | varchar(100) | YES | | | |
| email | varchar(100) | YES | | | |
| contact | varchar(130) | YES | | | | |
|
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