How to add a column and set primary key in a table through t-sql

Add a Column to a Table:

Syntax: ALTER TABLE TableName add columnName DataType NULL/NOT NULL

Example: ALTER TABLE Employee add IsDeleted bit NULL

Add a Primary Key To aTable:

Syntax: ALTER TABLE TableName add PRIMARY KEY(ColumnName)

Example: ALTER TABLE AddressType add PRIMARY KEY(AddressTypeID)

Note: PrimaryKey:Don’t Allow duplicates.