Question

我在选择时收到此错误。

DECLARE @TopID INT
SELECT @TopID = MAX([QuestionId]) from [SurveyQuestions];

 SELECT
       @TopID = @TopID + 1   
       ,[questiontext]
      ,[DeptID]
      ,[SurveyID]   
  FROM [SOSS].[dbo].[SurveyQuestions] where surveyid =80

为变量赋值的SELECT语句不能是结合数据检索操作。

我知道在将身份设置为ON时可以修复此错误。但我不希望这样，因为我的数据库托管在legecy应用程序中，更改此设置会使其他事情中断。

Answer 1

这与身份无关。它与select有关。你有：

  SELECT  @TopID = @TopID + 1, 
         [questiontext], [DeptID], [SurveyID]   
  FROM [SOSS].[dbo].[SurveyQuestions]
  WHERE surveyid = 80

这有一个赋值和它返回值。我想你真的想要：

  SELECT @TopId + (ROW_NUMBER() OVER (ORDER BY (SELECT NULL))) as rownum, 
         [questiontext], [DeptID], [SurveyID]   
  FROM [SOSS].[dbo].[SurveyQuestions]
  WHERE surveyid = 80;

注意：如果您确实希望按特定顺序排列结果，请将ORDER BY 两者添加到查询和ROW_NUMBER()。

Answer 2

这是您选择的方式，您无法在选择其他列时使用运算符。请参阅此link，了解您做错了什么。

我认为你真正需要的是：

DECLARE @TopID INT
SELECT @TopID = MAX([QuestionId]) from [SurveyQuestions];

 SELECT
       @TopID + 1   
       ,[questiontext]
      ,[DeptID]
      ,[SurveyID]   
  FROM [SOSS].[dbo].[SurveyQuestions] where surveyid =80

编辑： 或者基于ROW_NUMBER的解决方案，如：

    DECLARE @TopID INT
    SELECT @TopID = MAX([QuestionId]) from [SurveyQuestions];

     SELECT
           @TopID + ROW_NUMBER() OVER (ORDER BY (SELECT 1)) as TopID 
           ,[questiontext]
          ,[DeptID]
          ,[SurveyID]   
      FROM [SOSS].[dbo].[SurveyQuestions] where surveyid =80

改善先前答案的一点（合并为一个查询）：

 SELECT (
        SELECT TOP 1 QuestionId
        FROM SurveyQuestions
        ORDER BY QuestionId DESC
        ) 
+ ROW_NUMBER() OVER (   ORDER BY (SELECT 1)) AS TopID
, [questiontext], [DeptID], [SurveyID]
FROM [SOSS].[dbo].[SurveyQuestions]
WHERE surveyid = 80

SQL Fiddler

另一种选择，梳理您的2个查询：

SELECT
    (SELECT MAX(ID) FROM ForgeRock) as MAx_Id
    , ROW_NUMBER() OVER (ORDER BY (SELECT 1)) as Row_ID, 
    (SELECT TOP 1 ID FROM ForgeRock ORDER BY Id DESC) +
    ROW_NUMBER() OVER (ORDER BY (SELECT 1)) as New_Id,
    productName,
    description
FROM
    ForgeRock

SQL Fiddler

如何将带有标识的行id强制为off

2 个答案: