sql - 将列添加到 SQL Server 数据库中的表并使用案例设置默认值

Question

我需要在表 Major 中添加一个列 IsDeleted，默认值为: 当 MajorName 像 '%Engineering%' 时为真，而在其他没有单词 Engineering 的时候为假

Answer 1

将其添加为 computed column (又名虚拟列)

alter table Major add IsDeleted as 
    cast (case when MajorName like '%Engineering%' then 1 else 0 end as bit)

---

演示

create table Major (MajorName varchar (100))

alter table Major add IsDeleted as 
    cast (case when MajorName like '%Engineering%' then 1 else 0 end as bit)

insert into Major (MajorName) values 
    ('This is the Engineering department'),('Hello world')

select * from Major

---

+------------------------------------+-----------+
| MajorName                          | IsDeleted |
+------------------------------------+-----------+
| This is the Engineering department | 1         |
+------------------------------------+-----------+
| Hello world                        | 0         |
+------------------------------------+-----------+