Add column in table of Oracle, Sql Server, Mysql & Postgresql
Sometime after creating the database schema and sturture we have to modified or add column in the table for future updates. So we need to modified the structure of the tables for future deployment. We can use this command to add column in databases.
Following are the example of add column in the table
Syntax:
ALTER TABLE
ADD datatype;
Example
Suppose need to add one more column in employee table alter table employee add dateofjoin datetime;
SQL Server
ALTER TABLE table_name ALTER COLUMN column_name datatype;
ALTER TABLE dbo.table_name DROP COLUMN column_name;
Oracle
Alter table table_name modify column_name datatype;
alter table table_name drop column col_name1;
MySQL
ALTER TABLE MODIFY COLUMN datatype;
ALTER TABLE DROP ;
PostgreSQL
ALTER TABLE ADD COLUMN datatype ;
ALTER TABLE DROP COLUMN RESTRICT;
