Add a column and set primary key in a table through query

In many situations we need to modify the table definition in database. I am showing how to add a Column to a Table.

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

Example: ALTER TABLE Employee add usercategory varchar(50) NULL

in code we are adding a new column usercategory table. Now we are adding a primary key in table.

Syntax: ALTER TABLE TableName add PRIMARY KEY(ColumnName)

Example: ALTER TABLE AddressType add PRIMARY KEY(AddressTypeID)

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