Question

我有一个查询，我需要从表中获取结果，具体取决于用户在vb.net页面上指定的参数。

声明一个变量将是理想的解决方案，但由于它是一个内联表值函数，我无法做到这一点，我已经读过其他问题，这在多元表函数中是可行的但是使用了这样的不推荐使用功能。

以下查询将是理想的解决方案或我想要实现的目标。

 USE [AUDIT]
 GO

ALTER FUNCTION [dbo].[GetCreated_LPA_Audits]
(   
@fechaInicio nvarchar (max),
@fechaFin nvarchar (max)
@Period int,
@Fecha int

)
RETURNS TABLE 
AS
RETURN 
(

SELECT T1.Plant,T1.Area,T1.Location,T1.IDAudit,T1.Auditor,T1.AuditDate,T1.DueDate,T1.CreationDate
FROM Header AS T1 inner join Audits AS T2 ON T1.IDChecklist = T2.IDChecklist
inner join AuditGroups AS T3 ON T2.IDGroup = T3.IDGroup 

  WHERE T3.IDGroup = '2' and CreationDate is not null AND
   CASE WHEN @Periodo = '0' THEN CreationDate>= @fechaInicio
        WHEN @Periodo = '1' THEN DATEPART(MONTH,CreationDate)>= @Fecha
        WHEN @Periodo = '2' THEN 
                               CASE WHEN @Fecha = 13 THEN 
                                                     DATEPART(MONTH,CreationDate)>= 1
                               END
        WHEN @Periodo = '2' THEN 
                               CASE WHEN @Fecha = 14 THEN 
                                                     DATEPART(MONTH,CreationDate)>= 7
                               END
        WHEN @Periodo = '3' THEN 
                               CASE WHEN @Fecha = 15 THEN 
                                                     DATEPART(Year,CreationDate)>= 2015
                               END
   END
   AND

CASE WHEN @Periodo = '0' THEN  @fechaInicio<=CreationDate
     WHEN @Periodo = '1' THEN  @Fecha<=DATEPART(MONTH,CreationDate)
     WHEN @Periodo = '2' THEN 
                               CASE WHEN @Fecha = 13 THEN 
                                                     6<=DATEPART(MONTH,CreationDate)
                               END
        WHEN @Periodo = '2' THEN 
                               CASE WHEN @Fecha = 14 THEN 
                                                     12<=DATEPART(MONTH,CreationDate)
                               END
        WHEN @Periodo = '3' THEN 
                               CASE WHEN @Fecha = 15 THEN 
                                                     DATEPART(Year,CreationDate)>= 2015
                               END
   END

和在上一个查询@fechaInicio中，@ fefFin，@ Periodo和@Fecha是用户提供的参数。

基本上如果@Periodo = 0我需要将结果放在哪里 CreationDate>= @fechaInicio and CreationDate<=@fechaFin

如果@Periodo = 1我需要将结果放在哪里 DATEPART(MONTH,CreationDate)>= @Fecha and DATEPART(MONTH,CreationDate)<= @Fecha

等等。希望我提前做好准备，谢谢！

编辑使用来自@MatBailie的伪代码，并对其问题进行了一些修改和回答

IF @periodo = '0' THEN
    WHERE CreationDate  >= @fechaInicio  -- Copied from 1st CASE
      AND @fechaFin <= CreationDate   -- Copied from 2nd CASE

   -- gets results from @fechaInicio to @fechaFin
   -- i.e. results from 04/05/2016  to 04/16/2016

IF @periodo = '1' THEN
    WHERE DATEPART(MONTH,CreationDate) >= @Fecha   -- Copied from 1st CASE
      AND @Fecha <= DATEPART(MONTH,CreationDate)   -- Copied from 2nd CASE

    -- In these case both conditions are the same 'cause 
    -- @Fecha is the number of a month (1 - 12)
    -- i.e. @Fecha = 3 will get all the results of March
    -- regardless of what it is on @fechaInicio and @fechaFin

IF @periodo = '2' THEN
    IF @fetcha = 13 THEN
        WHERE DATEPART(MONTH,CreationDate)>= 1  -- Copied from 1st CASE
          AND 6<=DATEPART(MONTH,CreationDate)   -- Copied from 2nd CASE
    IF @fetcha = 14 THEN
        WHERE DATEPART(MONTH,CreationDate)>= 7  -- Copied from 1st CASE
          AND 12<=DATEPART(MONTH,CreationDate)  -- Copied from 2nd CASE

    -- You never use @fetchaInicio?
    -- You want everything in the first 6 months or last 6 months
    -- For every year
    -- Regardless of what is in @fetchaInicio?

    -- Exactly!!--

IF @periodo = '3' THEN
    IF @fetcha = 15 THEN
        WHERE DATEPART(Year,CreationDate)>= 2015  -- Copied from 1st CASE
          AND 2015 <= DATEPART(Year,CreationDate) -- Copied from 2nd CASE

    --

那个案例@periodo = '2' AND @fetcha NOT IN (13,14)怎么样？那个案例@periodo = '3' AND @fetcha NOT IN (15)？

怎么样？

此案例不存在，仅限于客户端。如果他们选择@Periodo = '2'，那么@Fecha的值将为1 - 12，而不是其他任何内容。

与@Periodo = '3'相同，则@Fecha的值为15或16，均指2015年或2016年。

Answer 1

重新组织WHERE子句要好得多，这样过滤后的字段位于左边，而不是任何函数内部。

例如......

WHERE
      CreationDate >= @VPeriodo
  AND CreationDate <  CASE
                        WHEN @Periodo = '0' THEN DATEADD(DAY,   1, @VPeriodo)
                        WHEN @Periodo = '1' THEN DATEADD(MONTH, 1, @VPeriodo)
                        WHEN @Periodo = '2' THEN DATEADD(MONTH, 1, @VPeriodo)
                        WHEN @Periodo = '3' THEN DATEADD(YEAR,  1, @VPeriodo)
                      END

在此示例中，右侧是所有标量常量。这意味着您可以在CreationDate字段上进行范围扫描。

另外，@ VPeriodo应该是DATE或DATETIME而不是VARCHAR(MAX)。

编辑： 包括使用VARCHAR跳转的箍

使用VARCHAR时，所有日期都需要采用YYYYMMDD格式。这是因为搅拌的自然顺序与日期的自然顺序相同...... - '20161101'＆gt; '20161002'

使用其他格式时，例如YYYYDDMM，它会失败...
- '20160111'＆lt; '20160210'问题，此格式于10月2日到11月1日之后

WHERE
      CreationDate >= @VPeriodo
  AND CreationDate <  CONVERT(
                        NVARCHAR(8),
                        CASE
                          WHEN @Periodo = '0' THEN DATEADD(DAY,   1, CAST(@VPeriodo AS DATE))
                          WHEN @Periodo = '1' THEN DATEADD(MONTH, 1, CAST(@VPeriodo AS DATE))
                          WHEN @Periodo = '2' THEN DATEADD(MONTH, 1, CAST(@VPeriodo AS DATE))
                          WHEN @Periodo = '3' THEN DATEADD(YEAR,  1, CAST(@VPeriodo AS DATE))
                        END,
                        112    -- Format code for ISO dates, YYYYMMDD
                      )

编辑： OP发出评论并改变问题后向OP提出的问题

我所做的就是重新安排你的代码，为你所写的内容制作伪代码......

IF @periodo = '0' THEN
    WHERE CreationDate  >= @fetchaInicio  -- Copied from 1st CASE
      AND @fetchaInicio <= CreationDate   -- Copied from 2nd CASE

    -- These two conditions are direct from your code
    -- But they're the same as each other
    -- What do you REALLY want to happen when @Periodo = '0'?

IF @periodo = '1' THEN
    WHERE DATEPART(MONTH,CreationDate) >= @Fecha   -- Copied from 1st CASE
      AND @Fecha <= DATEPART(MONTH,CreationDate)   -- Copied from 2nd CASE

    -- These two conditions are direct from your code
    -- But they're the same as each other
    -- What do you REALLY want to happen when @Periodo = '1'?

IF @periodo = '2' THEN
    IF @fetcha = 13 THEN
        WHERE DATEPART(MONTH,CreationDate)>= 1  -- Copied from 1st CASE
          AND 6<=DATEPART(MONTH,CreationDate)   -- Copied from 2nd CASE
    IF @fetcha = 14 THEN
        WHERE DATEPART(MONTH,CreationDate)>= 7  -- Copied from 1st CASE
          AND 12<=DATEPART(MONTH,CreationDate)  -- Copied from 2nd CASE

    -- You never use @fetchaInicio?
    -- You want everything in the first 6 months or last 6 months
    -- For every year
    -- Regardless of what is in @fetchaInicio?

IF @periodo = '3' THEN
    IF @fetcha = 15 THEN
        WHERE DATEPART(Year,CreationDate)>= 2015  -- Copied from 1st CASE
          AND DATEPART(Year,CreationDate)>= 2015  -- Copied from 2nd CASE

    -- Both conditions are the same again, why?
    -- You want everything from 2015 onwards, forever?
    -- You never use @fetchaInicio?
    -- It's always 2015?

那个案例@periodo = '2' AND @fetcha NOT IN (13,14)怎么样？那个案例@periodo = '3' AND @fetcha NOT IN (15)怎么样？

请你带上我的伪代码，并给出一些你在每种情况下真正想要做的实例吗？

Answer 2

每当您想在where子句中使用参数作为条件时，您可以遵循以下格式：

WHERE 
((@Periodo = '0' AND CreationDate
OR (@Periodo = '1' AND @VPeriodo = CAST(DATEPART(MONTH,CreationDate) as Nvarchar(10))
OR (@Periodo = '2' AND @VPeriodo = CAST(DATEPART(MONTH,CreationDate) as Nvarchar(10))
OR (@Periodo = '3' AND @VPeriodo = CAST(DATEPART(Year,CreationDate) as Nvarchar(10)))

确保参数评估是第一个，因为它会很快而且为false将阻止查询继续处理条件中处理更加密集的部分。

Answer 3

首先，你是对的，内联TFV真的更快。如果不是过于复杂。我最好为SQL Server端的每个@Periodo参数值设置一些iTFV，并在客户端的代码中选择正确的一个。

或者你可以在一个iTVF

中完成

WHERE 
  @Periodo = '0' AND  CreationDate>= @fechaInicio and CreationDate<=@fechaFin
  OR @Periodo = '1' and DATEPART(MONTH,CreationDate)>= @Fecha and DATEPART(MONTH,CreationDate)<= @Fecha
  ...

但是，众所周知，MS SQL会为OR运营商构建一个非常糟糕的计划，这可能会让你努力坚持使用iTVF。

WHERE子句中的CASE

3 个答案: