Question

我的问题是如何以智能方式改进查询字符串？

我想在参数为null时使用来自DB的参数查询数据，它将被删除。

我的查询字符串如下所示：

ALTER procedure [dbo].[spQueryDataFromCPREFROM]
@CompanyName varchar(50),
@TestDDL varchar(20),
@TesterName varchar(50),
@DatepickerForTestDate datetime,
@ApplyDate datetime,
@TestTypeDDL varchar(1),
@QueryString nvarchar(max)
as
begin
    if @CompanyName is not null 
       and @TestDDL is not null 
       and @TesterName is not null
       and @DatepickerForTestDate is not null
       and @ApplyDate is not null
       and @TestTypeDDL is not null
       and @QueryString is not null 
       begin 
            select @QueryString = 'select * from [dbo].[CPREFROM] as CF where CF.[UNIT_TID] ='+ @CompanyName 
                                    +'and CF.[ELIGIBLE_RATING] ='+ @TestDDL 
                                    +'and CF.[Name] =' + @TesterName
                                    +'and CF.[CHECKDATE] ='+ @DatepickerForTestDate
                                    +'and CF.[APPLYDATE] =' + @ApplyDate
                                    +'and CF.[A_S] =' + @TestTypeDDL
       end
     else if @CompanyName is null 
            and @TestDDL is not null 
            and @TesterName is not null
            and @DatepickerForTestDate is not null
            and @ApplyDate is not null
            and @TestTypeDDL is not null
            and @QueryString is not null 
            begin 
                select @QueryString = 'select * from [dbo].[CPREFROM] as CF where CF.[ELIGIBLE_RATING] ='+ @TestDDL 
                                    +'and CF.[Name] =' + @TesterName
                                    +'and CF.[CHECKDATE] ='+ @DatepickerForTestDate
                                    +'and CF.[APPLYDATE] =' + @ApplyDate
                                    +'and CF.[A_S] =' + @TestTypeDDL
            end
    ...

Answer 1

以下可以为您提供帮助吗？例如：

＆＃34; CF [UNIT_TID] = CF [UNIT_TID]＆＃34。与1 = 1相同

        select @QueryString = 'select * from [dbo].[CPREFROM] as CF where CF.[UNIT_TID] ='+ ISNULL(@CompanyName,'CF.[UNIT_TID]') 
                                +'and CF.[ELIGIBLE_RATING] ='+ ISNULL(@TestDDL,'CF.[ELIGIBLE_RATING]')
                                +'and CF.[Name] =' + ISNULL(@TesterName,'CF.[Name]')
                                +'and CF.[CHECKDATE] ='+ ISNULL(@DatepickerForTestDate,'CF.[CHECKDATE]')
                                +'and CF.[APPLYDATE] =' + ISNULL(@ApplyDate,'CF.[APPLYDATE]')
                                +'and CF.[A_S] =' + ISNULL(@TestTypeDDL,'CF.[A_S]')

但是如果可能的值为null，则需要使用ISNULL来处理该值因为＆＃34; NULL = NULL＆＃34;不是真的。

样品：

+'and ISNULL(CF.[Name],'''') =' + ISNULL(@TesterName,'ISNULL(CF.[Name],'''')')

T-SQL动态查询

1 个答案: