如何有條件地添加WHERE子句而不使用CASE

Question

我想在存儲過程的WHERE部分中有條件地添加子句，但我明白使用CASE非常糟糕。這基本上是我想要做的：

@StartDate 
@EndDate 
@ClientID 
SELECT field_1, field_2, datefield_3 
from tblTable 
Where datefield_3 Between @StartDate AND @EndDate 
--If @ClientID > 0 then add 
AND field_1 = @ClientID 

有什麼建議嗎？

Answer 1

一樣簡單：

@StartDate 
@EndDate 
@ClientID 
SELECT field_1, field_2, datefield_3 
from tblTable 
Where datefield_3 Between @StartDate AND @EndDate 
    AND (@ClientID <= 0 OR field_1 = @ClientID) 

如果@ClientID < = 0時，附加條件沒有進行評價。即如果@ClientID> 0，field_1 = @ClientID被評估！

Answer 2

這：

... 
Where datefield_3 Between @StartDate AND @EndDate 
AND (field_1 > 0 OR field_1 = @ClientID) 

Answer 3

@StartDate 
@EndDate 
@ClientID 


IF ClientID>0 
BEGIN 
SELECT field_1, field_2, datefield_3 
from tblTable 
Where datefield_3 Between @StartDate AND @EndDate 
AND field_1 = @ClientID 
END 
ELSE 
BEGIN 
    SELECT field_1, field_2, datefield_3 
from tblTable 
Where datefield_3 Between @StartDate AND @EndDate 
END