Question

我在case语句中实现了多个条件，如下所示，

select officied from budgettable
where budgetid = case @budgetid when 7 then 7
                when 7 then  8
                when 7 then 10
                when 8 then 6
          end

但它没有给我任何结果。如果我将预算ID称为7，则查询应返回8,10,7预算ID。上述查询有什么问题吗？

Answer 1

我怀疑你想要这样的东西：

where budgetid = @budgetid or
      (@budgetid = 7 and budgetid in (7, 8, 10)) or
      (@budgetid = 8 and budgetid = 6)

您的查询失败，因为@budgetid除了7或8之外的所有值，case都会返回NULL - 这被视为错误。

Answer 2

一种选择是使用case作为布尔表达式，在满足条件时返回1：

select officied from budgettable
where 1 = case 
      when @budgetid = budgetid then 1
      when @budgetid = 7 and budgetid in (7,8,10) then 1 
      when @budgetid = 8 and budgetid in (6,8) then 1 
      end

这会将@budgetid 7返回的结果扩展为包含8和10。

Answer 3

这不是答案。我只是想表明CASE WHEN如何运作，所以你看到了你的错误。您的查询评估Sub test_Wanceslas() Dim Ws As Worksheet, _ Rg As Range, _ LastRow As Long, _ Count As Long, _ ii As Long ii = 21 ' first page break Set Ws = ActiveSheet With Ws LastRow = .Range("A" & .Rows.Count).End(xlUp).Row Count = LastRow Set Rg = .Range("A1", "K" & Count) 'The range of the document If LastRow > 30 Then ' count is the number of row. Break at every 15 rows .ResetAllPageBreaks .PageSetup.PrintArea = Rg.Address While Count > 0 And ii < LastRow If Count > 15 Then ' no page break if there is less than 15 rows left '.Rows(ii).PageBreak = xlPageBreakManual .HPageBreaks.Add Before:=.Rows(ii) End If ii = ii + 15 Count = Count - 15 Wend End If End With End Sub，如下所示：

当7然后7 =＆gt; @budgetid 7
当7然后8 =＆gt;被忽略了，因为我们已经说过为@budgetid 7
当7然后10 =＆gt;被忽略了，因为我们已经说过为@budgetid 7
当8然后6 =＆gt; @budgetid 8
end =＆gt;别的没有，所以任何其他@budgetid都会导致NULL。

然后将结果与case @budgetid进行比较。对于NULL，这永远不会成立。所以你最终得到：

= budgetid

Answer 4

这会有效!!

SELECT
    officied
FROM
    budgettable
WHERE
    1 = 1
AND
    1 = CASE
              WHEN
                @budgetid = budgetid THEN 1
              WHEN
                (@budgetid = 7 AND budgetid IN (7,8,10)) THEN 1
              WHEN
                (@budgetid = 8 AND budgetid IN (6,8) THEN) 1
          END

更好的解决方案：添加新列 is_budget_calculated （数据类型BIT）并将其更新为0并保持为1。

在Case语句中使用多个条件

4 个答案: