如何在 SQL Server 2008 表中创建计算列

How to create a calculated column in a SQL Server 2008 table

提问by BI Dude

I really need a calculated column on a table with simple sum.

我真的需要一个简单总和的表格上的计算列。

Please see below:

请参阅以下内容：

SELECT   key3
         ,SUM(UTOTALWBUD)
FROM     CONTACT1
         INNER JOIN CONTACT2
            ON CONTACT1.ACCOUNTNO = CONTACT2.ACCOUNTNO
WHERE    KEY1 = 'Client'
GROUP BY KEY3

I have tried to create a calculated column by adding following

我试图通过添加以下内容来创建一个计算列

ALTER TABLE ManagerTaLog
ADD         WeeklyBudget as (   SELECT
                                        key3
                                        ,SUM(UTOTALWBUD)
                            FROM        CONTACT1
                                        JOIN CONTACT2
                                            ON CONTACT1.ACCOUNTNO = CONTACT2.ACCOUNTNO
                            WHERE       KEY1 = 'Client'
                            GROUP BY    KEY3)

I got the error message:

我收到错误消息：

Msg 1046, Level 15, State 1, Line 4
Subqueries are not allowed in this context. Only scalar expressions are allowed.

消息 1046，级别 15，状态 1，第 4 行
在此上下文中不允许子查询。只允许使用标量表达式。

Please advise what can I do about it.

请告知我该怎么办。

Many thanks

非常感谢

Part 2

第2部分

I have create a function; however, i get null values please advise.

我创建了一个函数；但是，我得到空值，请告知。

CREATE FUNCTION [dbo].[SumIt](@Key3 varchar)
RETURNS TABLE 
AS
RETURN
(
SELECT      SUM(UTOTALWBUD)
FROM        CONTACT1
            JOIN CONTACT2
                ON CONTACT1.ACCOUNTNO = CONTACT2.ACCOUNTNO
            JOIN Phone_List
                ON CONTACT1.KEY3 = Phone_List.[Manager ]
WHERE       KEY1 = 'Client'
            AND Phone_List.[Manager ] = @Key3
GROUP BY [Manager ]

)
END

GO

Just select statment that returns values I wish to add to Phone_list table

只需选择返回我希望添加到 Phone_list 表的值的语句

SELECT      [Manager ]
            ,SUM(UTOTALWBUD)
FROM        CONTACT1
            JOIN CONTACT2
                ON CONTACT1.ACCOUNTNO = CONTACT2.ACCOUNTNO
            JOIN Phone_List
                ON CONTACT1.KEY3 = Phone_List.[Manager ]
WHERE       KEY1 = 'Client'
GROUP BY    [Manager ]

Table definitions

表定义

CREATE TABLE [dbo].[CONTACT1](
    [ACCOUNTNO] [varchar](20) NOT NULL,
    [COMPANY] [varchar](40) NULL,
    [CONTACT] [varchar](40) NULL,
    [LASTNAME] [varchar](15) NULL,
    [DEPARTMENT] [varchar](35) NULL,
    [TITLE] [varchar](35) NULL,
    [SECR] [varchar](20) NULL,
    [PHONE1] [varchar](25) NOT NULL,
    [PHONE2] [varchar](25) NULL,
    [PHONE3] [varchar](25) NULL,
    [FAX] [varchar](25) NULL,
    [EXT1] [varchar](6) NULL,
    [EXT2] [varchar](6) NULL,
    [EXT3] [varchar](6) NULL,
    [EXT4] [varchar](6) NULL,
    [ADDRESS1] [varchar](40) NULL,
    [ADDRESS2] [varchar](40) NULL,
    [ADDRESS3] [varchar](40) NULL,
    [CITY] [varchar](30) NULL,
    [STATE] [varchar](20) NULL,
    [ZIP] [varchar](10) NOT NULL,
    [COUNTRY] [varchar](20) NULL,
    [DEAR] [varchar](20) NULL,
    [SOURCE] [varchar](20) NULL,
    [KEY1] [varchar](20) NULL,
    [KEY2] [varchar](20) NULL,
    [KEY3] [varchar](20) NULL,
    [KEY4] [varchar](20) NULL,
    [KEY5] [varchar](20) NULL,
    [STATUS] [varchar](3) NOT NULL,
    [NOTES] [text] NULL,
    [MERGECODES] [varchar](20) NULL,
    [CREATEBY] [varchar](8) NULL,
    [CREATEON] [datetime] NULL,
    [CREATEAT] [varchar](5) NULL,
    [OWNER] [varchar](8) NOT NULL,
    [LASTUSER] [varchar](8) NULL,
    [LASTDATE] [datetime] NULL,
    [LASTTIME] [varchar](5) NULL,
    [U_COMPANY] [varchar](40) NOT NULL,
    [U_CONTACT] [varchar](40) NOT NULL,
    [U_LASTNAME] [varchar](15) NOT NULL,
    [U_CITY] [varchar](30) NOT NULL,
    [U_STATE] [varchar](20) NOT NULL,
    [U_COUNTRY] [varchar](20) NOT NULL,
    [U_KEY1] [varchar](20) NOT NULL,
    [U_KEY2] [varchar](20) NOT NULL,
    [U_KEY3] [varchar](20) NOT NULL,
    [U_KEY4] [varchar](20) NOT NULL,
    [U_KEY5] [varchar](20) NOT NULL,
    [recid] [varchar](15) NOT NULL
) ON [PRIMARY] TEXTIMAGE_ON [PRIMARY]

GO



CREATE TABLE [dbo].[Phone_List](
    [Manager ] [nvarchar](255) NULL,
    [SalesCode] [nvarchar](255) NULL,
    [Email] [nvarchar](255) NULL,
    [PayrollCode] [nvarchar](255) NULL,
    [Mobile] [nvarchar](255) NULL,
    [FName] [nchar](20) NULL,
    [idd] [tinyint] NULL,
    [OD] [varchar](20) NULL,
    [WeeklyBudget]  AS ([dbo].[SumIt]([manager]))
) ON [PRIMARY]

回答by Oleg Dok

You can wrap your query into the function like this (it HASto return one value):

你可以用你的查询到这样的（它的功能HAS返回一个值）：

CREATE FUNCTION dbo.SumIt(@Key1 varchar(max))
returns float
as
begin
  return (select sum(UTOTALWBUD) from
   CONTACT1 inner join
   CONTACT2 on
   CONTACT1.ACCOUNTNO=CONTACT2.ACCOUNTNO
   where KEY1=@key1
   group by KEY3)
END

And use this function instead with calc field - something like this:

并使用此函数代替 calc 字段 - 如下所示：

alter table ManagerTaLog add WeeklyBudget as dbo.SumIt(Key1)

NOTE

笔记

that it will be the performance killer for queries like that:

它将成为这样的查询的性能杀手：

select * from ManagerTaLog 

You should change your function in such a way, that is accept NOTvarcharvalue, but NVARCHAR(255)- the same type as Manager column. Try it.

您应该以这种方式更改您的功能，即接受NOTvarchar值，但是NVARCHAR(255)- 与 Manager 列的类型相同。尝试一下。

回答by Lieven Keersmaekers

If you resolve the issue of returning two values, one solution would be to implement the calculation in a function and use this function for the calculated column.

如果您解决了返回两个值的问题，一种解决方案是在函数中实现计算并将此函数用于计算列。

Some considerations

一些注意事项

• I have assumed that it is Key3that needs to be passed to the function and have added a where clause to return the weekly budget for the given Key3value.
• The function will get executed for everyrecord in a resultset where you add the calculated column.

• 我假设它Key3需要传递给函数，并添加了一个 where 子句来返回给定Key3值的每周预算。
• 该函数将对结果集中的每条记录执行，您在其中添加了计算列。

Script

脚本

CREATE FUNCTION dbo.fn_ManagerTaLogWeeklyBudget(@Key3 INTEGER) RETURNS INTEGER AS 
BEGIN
  select sum(UTOTALWBUD) from
  CONTACT1 inner join
  CONTACT2 on
  CONTACT1.ACCOUNTNO=CONTACT2.ACCOUNTNO
  where KEY1='Client'
        AND KEY3 = @Key3
  group by KEY3)

END
GO

ALTER TABLE dbo.ManagerTaLog
ADD WeeklyBudget AS dbo.fn_ManagerTaLogWeeklyBudget(Key3)

回答by marc_s

You cannot have a subquery that returns multiple valuesto be used as the computed column expression.

不能有返回多个值的子查询用作计算列表达式。

You can have an expression that returns a single value- or you can wrap your code in a stored function - or you can create a view (with a JOIN or subquery) that combines this logic into something you can use

您可以使用返回单个值的表达式- 或者您可以将代码包装在存储函数中 - 或者您可以创建一个视图（使用 JOIN 或子查询），将这个逻辑组合成您可以使用的东西

回答by Daniel

IMHO It is a wrong way. You have to use trigger on CONTACT tables and update WeeklyBudget in these triggers.

恕我直言，这是一种错误的方式。您必须在 CONTACT 表上使用触发器并在这些触发器中更新 WeeklyBudget。

回答by Gopakumar N.Kurup

CREATE FUNCTION [dbo].[SumIt](@Key3 varchar)
RETURNS TABLE 
AS
RETURN
(
SELECT      SUM(ISNULL(UTOTALWBUD,0))
FROM        CONTACT1
            JOIN CONTACT2
                ON CONTACT1.ACCOUNTNO = CONTACT2.ACCOUNTNO
            JOIN Phone_List
                ON CONTACT1.KEY3 = Phone_List.[Manager ]
WHERE       KEY1 = 'Client'
            AND Phone_List.[Manager ] = @Key3
GROUP BY [Manager ]

)
END

GO

Hope this will help. Please note that this is not a proper solution, but this may help your particular scenario. Since the function is returning multiple values, you can either user a table valued function or just modify the query in a way that it will return only one value. But if the column is nullable please don't forget to add ISNULL.

希望这会有所帮助。请注意，这不是一个正确的解决方案，但这可能对您的特定情况有所帮助。由于该函数返回多个值，您可以使用表值函数或仅以仅返回一个值的方式修改查询。但如果该列可以为空，请不要忘记添加 ISNULL。

回答by mshthn

You can have calculated columns in a table but that will be present (and calculated) in all rows of the table. The thing what you're trying to do in your select is called "aggregate". Try this:

您可以在表中计算列，但这些列将出现（并计算）在表的所有行中。您在选择中尝试做的事情称为“聚合”。尝试这个：

select key3, sum(UTOTALWBUD) as WeeklyBudget from
CONTACT1 inner join CONTACT2 on CONTACT1.ACCOUNTNO=CONTACT2.ACCOUNTNO
where KEY1='Client' 
group by key3