Question

以下是存储过程的一部分： -

@ID int
@Col1 int
@Col2 int

Select * 
from Table_01 t1
JOIN table_02 t2 on t1.col = t2.col
where 
  1 = case when @Col1 = 0 then 1 else (case when t2.Col1 = @Col1 then 1 else 0 end) end
  AND 1 = case when @Col2 = 0 then 1 else (case when t2.Col2 = @Col2 then 1 else 0 end) end
  AND 1 = case when @ID = 0 then 1 else (case when t2.ID = @ID then 1 else 0 end) end

目前

如果@ID = 0则忽略条件
如果@ID有值，则它会根据条件满意度

我需要在那里添加另一个条件： -

if @ID = -1然后不应该返回任何结果（因为没有匹配）但它应该像@ID = 0（忽略添加表达）

我清楚了吗？：（

Answer 1

Select ...
From Table_01 As t1
    Join table_02 As t2 
        On t1.col = t2.col
Where Case 
        When @ID = 0 Then 1 
        When t2.ID = @ID Then 1 
        When @ID = -1 Then 0
        Else 0 
        End = 1

如果最后一个条件胜过其他两个条件，则需要更改顺序：

Select ...
From Table_01 As t1
    Join table_02 As t2 
        On t1.col = t2.col
Where Case 
        When @ID = -1 Then 0
        When @ID = 0 Then 1 
        When @ID = t2.ID Then 1 
        Else 0 
        End = 1

当然，另一种可能表现更好的方式（假设@ID = -1胜过）：

Select ...
From Table_01 As t1
    Join table_02 As t2 
        On t1.col = t2.col
Where @ID != -1 
    And ( @ID = 0 Or @ID = t2.ID )

根据OP的修改进行更新

听起来你正在尝试做类似以下的事情：

Select ...
From Table_01 As t1
    Join table_02 As t2 
        On t1.col = t2.col
Where @ID != -1
    And ( @Col1 = 0 Or @Col1 = t2.Col1 )
    And ( @Col2 = 0 Or @Col2 = t2.Col2 )
    And ( @ID = 0 Or @ID = t2.ID )

Answer 2

我会尝试写它以便更清楚：

WHERE @ID IN (0, t2.ID) AND @ID <> -1

或

WHERE (@ID = 0 OR t2.ID = @ID) AND @ID <> -1

如果t2.ID不能为-1，则表示您不需要该部分。

Answer 3

如果我理解正确，您只需要@ID = -1与@ID = 0具有相同的效果。在这种情况下，您的查询可能如下所示：

Select * 
FROM Table_01 t1
  JOIN table_02 t2 on t1.col = t2.col
WHERE @Col1 IN (0, t2.Col1)
  AND @Col2 IN (0, t2.Col2)
  AND @ID IN (-1, 0, t2.ID)

如何在sql的条件下使用大小写？

3 个答案: