sql-server - SQL Server 中没有唯一列时如何设置主键？

Question

当几乎所有列都有冗余数据时，如何在现有表上设置主键？

标签： sql-server

Answer 1

 ALTER Table, Add [Table].[Id] column as Identity seed 1 increment 1, save.

 Right click [Id] column, set as primary key, save. Done.

SQL 服务器将自动添加递增值

T-SQL：

-- add new "Id" column, make it IDENTITY (= auto-incrementing)
ALTER TABLE dbo.YourTable 
ADD Id INT IDENTITY(1,1)
GO

-- add new primary key constraint on new column   
ALTER TABLE dbo.YourTable 
ADD CONSTRAINT PK_YourTable
PRIMARY KEY CLUSTERED (Id)
GO