Mysql Alter Add Column
Mysql Alter Add Column is used to define the existing Table and add a new column to it.
Understand with Example
The Tutorial demonstrate you 'Mysql Alter Add Column'. To understand this example, we create a table employees using create table statement in Mysql. The table employees has a Empid as Primary Key.
Query to create table:
CREATE TABLE `employees` (
->Empid int(10),
->Empname varchar(60),
->date date
->PRIMARY KEY(Empid)
->);
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Query to insert data into Table named employees:
The insert into add the records or rows into table 'employees'.
mysql>insert into employees values(01,'Girish','2008-12-22'); Query OK, 1 row affected (0.02 sec) mysql>insert into employee1 values(02,'Komal','2008-12-23'); Query OK, 1 row affected (0.02 sec) |
Query to view data of Table named employees:
To view the detail from table 'employees' we use select query that return you the details.
mysql> select * from employees; |
Output:-
+-------+---------+------------+ | Empid | Empname | date | +-------+---------+------------+ | 1 | Girish | 2008-12-22 | | 2 | Komal | 2008-12-23 | +-------+---------+------------+ 2 rows in set (0.00 sec) |
Query to alter Table named employees by adding column named city:
The Query Alter is used to define the table 'employees' and add a new column 'city' to the existing table 'employees'.
mysql> alter table employees
-> add column city varchar(30);
Query OK, 2 rows affected (0.13 sec)
Records: 2 Duplicates: 0 Warnings: 0
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Output:-
mysql> select * from employees; +-------+---------+------------+------+ | Empid | Empname | date | city | +-------+---------+------------+------+ | 1 | Girish | 2008-12-22 | NULL | | 2 | Komal | 2008-12-23 | NULL | +-------+---------+------------+------+ 2 rows in set (0.02 sec) |