Possible Duplicate:
Add column, with default value, to existing table in SQL Server可能重复：将具有默认值的列添加到SQL Server中的现有表
I have a table in sql server, but want to add a extra column full of zeros
我在sql server中有一个表，但是想要添加一个充满零的额外列
What would be the best approach to do this
什么是最好的方法来做到这一点
att1 att2
---------
1.0 5.8
2.7 3.8
5.1 6.8
becomes
变
att1 att2 extra
----------------
1.0 5.8 0.0
2.7 3.8 0.0
5.1 6.8 0.0
2 个解决方案
#1
11
If I recall correctly, it should be something like:
如果我没记错的话，应该是这样的：
ALTER TABLE table_name
ADD extra REAL DEFAULT 0
See: http://msdn.microsoft.com/en-us/library/ms190273.aspx
请参阅：http：//msdn.microsoft.com/en-us/library/ms190273.aspx
See: Add a column with a default value to an existing table in SQL Server
请参阅：将具有默认值的列添加到SQL Server中的现有表
#2
3
I understand this column will always have value of 0.0. Then it does not have to be a real column
我知道这个列的值总是为0.0。那么它不一定是真正的专栏
CREATE TABLE extraColumn (
att1 float NULL
,att2 float NULL
,extra AS 0.0
)
But if you need that, you can persist it
但如果你需要，你可以坚持下去
CREATE TABLE extraColumn (
att1 float NULL
,att2 float NULL
,extra AS 0.0 PERSISTED
)
#1
11
If I recall correctly, it should be something like:
如果我没记错的话，应该是这样的：
ALTER TABLE table_name
ADD extra REAL DEFAULT 0
See: http://msdn.microsoft.com/en-us/library/ms190273.aspx
请参阅：http：//msdn.microsoft.com/en-us/library/ms190273.aspx
See: Add a column with a default value to an existing table in SQL Server
请参阅：将具有默认值的列添加到SQL Server中的现有表
#2
3
I understand this column will always have value of 0.0. Then it does not have to be a real column
我知道这个列的值总是为0.0。那么它不一定是真正的专栏
CREATE TABLE extraColumn (
att1 float NULL
,att2 float NULL
,extra AS 0.0
)
But if you need that, you can persist it
但如果你需要，你可以坚持下去
CREATE TABLE extraColumn (
att1 float NULL
,att2 float NULL
,extra AS 0.0 PERSISTED
)