Create View - Declare a variable

问题

I am creating a view that is using that STUFF function. I want to put the result of STUFF in a variable for my view. The problem I am having is declaring my variable. It gives me the message "Incorrect Syntax near 'DECLARE'. Expecting '(' or SELECT." I already have the '(' in there. I have tried putting a BEGIN before it. I have tried putting it after the SELECT word. But nothing seems to work and I cannot find a solution in my search. I am using SQL Server 2012

CREATE VIEW [AQB_OB].[GISREQUESTEDBURNS] 
AS

(DECLARE @CONDITIONS AS varchar(20)
SET @CONDITIONS = (SELECT DISTINCT BD.[RequestedBurnsID]
,[ConditionsReasonsID] = STUFF((SELECT ', ' + CONVERT(VARCHAR (20),[ConditionsReasonsID]) FROM [AQB_OB].[BurnDecisions] WHERE [RequestedBurnsID]= BD.[RequestedBurnsID] ORDER BY [RequestedBurnsID] ASC
FOR XML PATH ('')) , 1 , 1, '') FROM
[AQB_OB].[BurnDecisions] BD)

SELECT RB.[RequestedBurnsID] AS REQUESTEDBURNID
  ,BUY.[BurnYear] AS BURNYEAR
  ,CY.[CurrentYear] AS CURRENTYEAR
  ,RB.[BurnSitesID] AS BURNSITESID
  ,[BurnerID] AS BURNERID
  ,[Contact] AS CONTACT
  ,[BurnDecision] AS BURNDECISION
  ,RB.[Comment] AS COMMENT
  ,@CONDITIONS AS CONDITIONS
FROM [AQB_MON].[AQB_OB].[RequestedBurns] RB
LEFT join AQB_MON.[AQB_OB].[PileDryness] PD on RB.[PileDrynessID] = PD.[PileDrynessID]
inner join AQB_MON.[AQB_OB].[BurnYear] BUY on BUY.BurnYearID = BP.BurnYearID
inner join AQB_MON.[AQB_OB].[CurrentYear] CY on CY.CurrentYearID = BUY.CurrentYearID

GO

回答1:

You can't declare variables in a view. Could you make it into a function or stored procedure?

Edit - you might also be able to put something into a CTE and keep it as a view.

e.g.

with conditions as 
(
 ... do the STUFF here
)
select blah
from blah
inner join conditions
(or cross join conditions if its just one row, I can't quite decipher what your data is like)

回答2:

Try put the condition subquery directly inside the the view select statement. you may CAST the XML to VARCHAR(20).

CREATE VIEW [AQB_OB].[GISREQUESTEDBURNS] 
AS    
SELECT RB.[RequestedBurnsID] AS REQUESTEDBURNID
  ,BUY.[BurnYear] AS BURNYEAR
  ,CY.[CurrentYear] AS CURRENTYEAR
  ,RB.[BurnSitesID] AS BURNSITESID
  ,[BurnerID] AS BURNERID
  ,[Contact] AS CONTACT
  ,[BurnDecision] AS BURNDECISION
  ,RB.[Comment] AS COMMENT,

 (
     SELECT DISTINCT BD.[RequestedBurnsID],
             [ConditionsReasonsID] = STUFF((SELECT ', ' + CONVERT(VARCHAR (20),     [ConditionsReasonsID]) FROM [AQB_OB].[BurnDecisions] 
     WHERE [RequestedBurnsID]= BD.[RequestedBurnsID] ORDER BY [RequestedBurnsID] ASC
    FOR XML PATH ('')) , 1 , 1, '') FROM
    [AQB_OB].[BurnDecisions] BD
 ) AS CONDITIONS

FROM [AQB_MON].[AQB_OB].[RequestedBurns] RB
LEFT join AQB_MON.[AQB_OB].[PileDryness] PD on RB.[PileDrynessID] = PD.[PileDrynessID]
inner join AQB_MON.[AQB_OB].[BurnYear] BUY on BUY.BurnYearID = BP.BurnYearID
inner join AQB_MON.[AQB_OB].[CurrentYear] CY on CY.CurrentYearID = BUY.CurrentYearID

回答3:

Here is a sample query that uses CTE to nicely emulate internal variable construction, as described by James Casey. You can test-run it in your version of SQL Server.

CREATE VIEW vwImportant_Users AS
WITH params AS (
    SELECT 
    varType='%Admin%', 
    varMinStatus=1)
SELECT status, name 
    FROM sys.sysusers, params
    WHERE status > varMinStatus OR name LIKE varType

SELECT * FROM vwImportant_Users

yielding output:

status  name
12      dbo
0       db_accessadmin
0       db_securityadmin
0       db_ddladmin

also via JOIN

WITH params AS ( SELECT varType='%Admin%', varMinStatus=1)
SELECT status, name 
    FROM sys.sysusers INNER JOIN params ON 1=1
    WHERE status > varMinStatus OR name LIKE varType

also via CROSS APPLY

WITH params AS ( SELECT varType='%Admin%', varMinStatus=1)
SELECT status, name 
    FROM sys.sysusers CROSS APPLY params
    WHERE status > varMinStatus OR name LIKE varType

来源：https://stackoverflow.com/questions/40809271/create-view-declare-a-variable

标签

sql

sql-server

declare