Question

我正试图找到一种方法来插入新记录，只有在表中不存在。

这是存储过程：

USE [ABSTest]
GO
/****** Object:  StoredProcedure [dbo].[sp_InsertBudgetCommessaInPreventivo]    Script     Date: 01/07/2013 09:12:16 ******/
SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO
-- =============================================
-- Author:      <Alex Ziani>
-- Create date: <04/01/2013>
-- Description: <Insert di valori con inserimento di parametri>
-- =============================================
ALTER PROCEDURE [dbo].[sp_InsertBudgetCommessaInPreventivo] 
@Progressivo                    nvarchar(50),
@Durata                         float,
@Costo                          money,
@CostoStandard                  money,
@Tariffa                        money,
@SpeseStandard                  money,
@Codice_Tipo                    nvarchar(50),
@Codice_FiguraProfessionale     nvarchar(10),
@Codice_Risorsa                 nvarchar(50),
@Codice_Commessa                nvarchar(20),
@Codice_ODL                     nvarchar(30),
@Task                           nvarchar(100)

AS
BEGIN
-- SET NOCOUNT ON added to prevent extra result sets from
-- interfering with SELECT statements.
SET NOCOUNT ON;

IF NOT EXISTS   (SELECT * FROM Preventivo WHERE Progressivo = @Progressivo 
            AND Quantita = @Durata 
            AND Costo = @Costo  
            AND CostoStandard = @CostoStandard 
            AND Tariffa = @Tariffa 
            AND SpeseStandard = @SpeseStandard 
            AND FkCodiceEnumTipoPreventivo = @Codice_Tipo 
            AND FkCodiceEnumFiguraProfessionale = @Codice_FiguraProfessionale
            AND FKCodiceRisorsa = @Codice_Risorsa 
            AND FkCodiceCommessa = @Codice_Commessa 
            AND FkCodiceOrdineDiLavoro = @Codice_ODL
            AND Task = @Task)               
BEGIN           
    INSERT INTO [ABSTest].[dbo].[Preventivo]
           ([Progressivo] 
           ,[Quantita] 
           ,[Costo]
           ,[CostoStandard]
           ,[Tariffa]
           ,[SpeseStandard]
           ,[FkCodiceEnumTipoPreventivo]
           ,[FkCodiceEnumFiguraProfessionale]
           ,[FKCodiceRisorsa]
           ,[FkCodiceCommessa]
           ,[FkCodiceOrdineDiLavoro]
           ,[Task])
     VALUES
           (@Progressivo
           ,@Durata
           ,@Costo
           ,@CostoStandard 
           ,@Tariffa
           ,@SpeseStandard 
           ,@Codice_Tipo 
           ,@Codice_FiguraProfessionale
           ,@Codice_Risorsa 
           ,@Codice_Commessa 
           ,@Codice_ODL
           ,@Task)
 END
 ELSE
 BEGIN
    RAISERROR 50001 'ERRORE: RECORD GIà PRESENTE'
 END
END

这样可以正常工作，但所有值（主键除外）都是Nullable，所以如果我将参数设置为Null，则它不起作用。如何使用Null来设计它？

Answer 1

您可以使用以下代码进行检查：

IF NOT EXISTS   (SELECT * FROM Preventivo WHERE ISNULL(Progressivo,'') = ISNULL(@Progressivo,'') 
        AND ISNULL(Quantita,0) = ISNULL(@Durata,0) 
        AND ISNULL(Costo,0) = ISNULL(@Costo,0)
        AND ISNULL(CostoStandard,0) = ISNULL(@CostoStandard,0)
        AND ISNULL(Tariffa,0) = ISNULL(@Tariffa,0)
        AND ISNULL(SpeseStandard,0) = ISNULL(@SpeseStandard,0)
        AND ISNULL(FkCodiceEnumTipoPreventivo,'') = ISNULL(@Codice_Tipo,'')
        AND ISNULL(FkCodiceEnumFiguraProfessionale,'') = ISNULL(@Codice_FiguraProfessionale,'')
        AND ISNULL(FKCodiceRisorsa,'') = ISNULL(@Codice_Risorsa,'') 
        AND ISNULL(FkCodiceCommessa,'') = ISNULL(@Codice_Commessa,'')
        AND ISNULL(FkCodiceOrdineDiLavoro,'') = ISNULL(@Codice_ODL,'')
        AND ISNULL(Task,'') = ISNULL(@Task,'') )

Answer 2

使用ISNULL作为比较运算符。可能会慢一点

SELECT * FROM Preventivo WHERE ISNULL(Progressivo, '') = ISNULL(@Progressivo, '')

Answer 3

您可以使用Case语句

来实现此目的

例如

AND Quantita = CASE @Durata
WHEN null THEN Quantita
ELSE @Durata

所以当@Durata == null的情况下会返回Quantita本身，所以结果将是真的（Quantita = Quantita）

Answer 4

对于null你需要输入条件

where column_name  is null

在您的原因中，您可以使用sql server中可用的IsNull()函数，如此

 where IsNull(column_name,-1) = Isnull(@variable,-1)

将变量值与列进行比较，如上所述，轻松解决问题

Answer 5

您的存储过程正在尝试

NULL = NULL

更改存储过程的第一个语句，它应该可以正常工作

SET ANSI_NULLS OFF;

如果您使用的是SQL 2008 R2或更高版本，请考虑使用MERGE语句。

拉吉

如何不插入具有空值的双记录

5 个答案: