SQL Server Alter

SQL Server Alter command is used to modify the structure of a table. With alter command we can add new column, drop column and modify the column.

Syntax:

Alter table table_name
add/drop/modify column datatype

Table structure is used in this example.
SQL-Server-Insert1

Examples:
Add new column to emp table
alter table emp
add email varchar(25)

Change the datatype of table column.
aleter table emp
alter column email varhcar(35) not null

Drop a column from the table emp.
alter table emp
drop column email

Add unique constraint to the table.
alter table emp
add constraint x unique(email)

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