如何在SQL Server 2012中的单个查询中使用更改表列和添加约束

Question

In MySQL I use:

alter table (table name)
    modify column name varchar(255) not null unique

How to use same query in SQL Server?

Thank you

Answer 1

I have not tested this. For SQL Server 2008 and above:

ALTER TABLE table_name
  ALTER COLUMN column_name varchar(255) not null;

Apparently, the unique constraint cannot be on the same command, so.. no, you can't put that in a single query:

ALTER TABLE table_name
  ADD CONSTRAINT constraint_name UNIQUE(column_name);

Change the table_name , column_name and constraint_name accordingly.

Reference: docs.microsoft.com - Alter Table (Transact-SQL)