Написание страшного поискового запроса SQL

Question

Я работаю над поисковым запросом, который, похоже, не работает.Полный запрос:

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)

Когда я передаю параметры в запрос, и если значение Vendor_Num не заполнено, вывод PRINT (@SQLstr) будет

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')

* 1006хотите, чтобы вывод был:

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')

Как мне структурировать запрос, чтобы, если значение параметра было пустым, поле не отображалось.

Answer 1

Попробуйте изменить

IF (@Vendor_Num IS NOT NULL) 

на

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