Rédaction d'une requête de recherche SQL redoutée

Question

Je travaille sur une requête de recherche qui ne semble pas fonctionner. La requête complète est:

set ANSI_NULLS ON 
set QUOTED_IDENTIFIER ON 
go 

ALTER PROCEDURE [dbo].[usp_Item_Search] 
    @Item_Num varchar(30) = NULL 
    ,@Search_Type int = NULL 
    ,@Vendor_Num varchar(10) = NULL 
    ,@Search_User_ID int = NULL 
    ,@StartDate smalldatetime = NULL 
    ,@EndDate smalldatetime = NULL 
AS 
DECLARE @SQLstr as nvarchar(4000) 

Set @SQLstr = 'SELECT RecID, Vendor_Num, Vendor_Name, InvoiceNum, Item_Num, 
(SELECT CONVERT(VARCHAR(11), RecDate, 106) AS [DD MON YYYY]) As RecDate, NeedsUpdate, RecAddUserID FROM [tbl_ItemLog] ' 

IF (@Item_Num IS NOT NULL) 
    Begin 
     If @Search_Type = 0 
      BEGIN 
       Set @SQLstr = @SQLstr + 'WHERE Item_Num LIKE ''' + @Item_Num + '%''' 
      END 
     If @Search_Type = 1 
      BEGIN 
       Set @SQLstr = @SQLstr + 'WHERE Item_Num LIKE ''%' + @Item_Num + '%''' 
      END 
     If @Search_Type = 2 
      BEGIN 
       Set @SQLstr = @SQLstr + 'WHERE Item_Num LIKE ''%' + @Item_Num + '''' 
      END 
    End 

IF (@Vendor_Num IS NOT NULL) 
    Begin 
     Set @SQLstr = @SQLstr + ' AND Vendor_Num = ''' + @Vendor_Num + '''' 
    End 

IF (Search_User_ID IS NOT NULL) 
    Begin 
     Set @SQLstr = @SQLstr + ' AND RecAddUserID = ' + convert(nvarchar(20),@Search_User_ID) 
    End 

Set @SQLstr = @SQLstr + ' AND (RecDate BETWEEN ''' + convert(nvarchar(10),@StartDate,101) + ''' AND ''' + convert(nvarchar(10),@EndDate,101) + ''')' 

PRINT (@SQLstr) 
--Execute (@SQLstr) 

Quand je passe paramters à la requête, et si la valeur de Vendor_Num est vide, la sortie PRINT (@SQLstr) est

SELECT RecID, Vendor_Num, Vendor_Name, InvoiceNum, Item_Num, 
(SELECT CONVERT(VARCHAR(11), RecDate, 106) AS [DD MON YYYY]) As RecDate, 
NeedsUpdate, RecAddUserID FROM [tbl_ItemLog] WHERE Item_Num LIKE '2200%' 
**AND Vendor_Num = ''** AND RecAddUserID = 2 AND (RecDate BETWEEN '01/01/2001' 
AND '12/12/2002') 

Ce que je veux la sortie être est:

SELECT RecID, Vendor_Num, Vendor_Name, InvoiceNum, Item_Num, 
(SELECT CONVERT(VARCHAR(11), RecDate, 106) AS [DD MON YYYY]) As RecDate, 
NeedsUpdate, RecAddUserID FROM [tbl_ItemLog] WHERE Item_Num LIKE '2200%' 
AND RecAddUserID = 2 AND (RecDate BETWEEN '01/01/2001' AND '12/12/2002') 

Comment puis-je structurer la requête si la valeur est vide param, il ne montre pas le champ.

Answer 1

Essayez de changer

IF (@Vendor_Num IS NOT NULL) 

à

IF (@Vendor_Num IS NOT NULL and LTRIM(@Vendor_Num) <> '')