添加表列在SQL Server數據庫中，使默認值與案件

Question

我需要一列IsDeleted添加到表Major用默認值將是： 真當MajorName像'%Engineering%'和虛假的人，其不有一句話工程

Answer 1

因爲其添加爲computed column（AKA虛擬列）

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   | 
+------------------------------------+-----------+ 

Answer 2

要添加列到表：

ALTER TABLE yourtable ADD IsDeleted bit ; 

要檢查MajorName並請將isDeleted集TO1或0使用Trigger