sql server alter table add primary key code example
Example 1: add primary key to existing table sql
alter table Persion add primary key (persionId,Pname,PMID)
Example 2: alter table add key sql server
ALTER TABLE Persons
ADD CONSTRAINT PK_Person PRIMARY KEY (ID,LastName);
Example 3: sql server add primary key to existing table with data
ALTER TABLE Production.TransactionHistoryArchive
ADD CONSTRAINT PK_TransactionHistoryArchive_TransactionID PRIMARY KEY CLUSTERED (TransactionID);