使用IF語句的條件WHERE子句SSRS 2005

Question

我在SSRS中遇到了一些麻煩，我認爲這應該是非常基本的。我已經看到了有關IIF聲明和其他內容的一些答案，但沒有完全解決這個問題。

我是SSRS的新手，所以我不確定在數據部分中使用PLSQL可以使用哪些代碼/語法。

我想要做的是有一個基於參數是否爲null的if語句。我嘗試了各種語法，但它一直在拋出錯誤。有什麼建議麼？

喜歡的東西：

IF (:start_date IS NULL) THEN 

SELECT wo.wonum, wo.worktype, wo.description wo_description, wo.targcompdate, wo.assetnum,   
s.siteid, s.description s_description, 
round((wo.targcompdate - sysdate), 0) DaysTillDue 
FROM workorder wo 
INNER JOIN site s on wo.siteid = s.siteid 
WHERE 
(wo.targcompdate - sysdate) >= :Low_Day 
and (wo.targcompdate - sysdate) <= :High_Day 
and wo.siteid = :site_param 
and wo.worktype = :worktype_param; 

ELSE 

SELECT wo.wonum, wo.worktype, wo.description wo_description, wo.targcompdate, wo.assetnum,   
s.siteid, s.description s_description, 
round((wo.targcompdate - sysdate), 0) DaysTillDue 
FROM workorder wo 
INNER JOIN site s on wo.siteid = s.siteid 
WHERE 
(wo.targcompdate - sysdate) >= :Low_Day 
and (wo.targcompdate - sysdate) <= :High_Day 
and wo.siteid = :site_param 
and wo.worktype = :worktype_param 
and targcompdate between :start_date and :end_date; 

END; 

Answer 1

您可以使用動態SQL表達式（雖然這一般是由於棄用事項，如SQL注入），但考慮到兩個查詢之間的唯一區別是額外的最終條件，我建議以下查詢，而不是：

SELECT wo.wonum, wo.worktype, wo.description wo_description, wo.targcompdate, 
     wo.assetnum, s.siteid, s.description s_description, 
     round((wo.targcompdate - sysdate), 0) DaysTillDue 
FROM workorder wo 
INNER JOIN site s on wo.siteid = s.siteid 
WHERE (wo.targcompdate - sysdate) >= :Low_Day 
    and (wo.targcompdate - sysdate) <= :High_Day 
    and wo.siteid = :site_param 
    and wo.worktype = :worktype_param 
    and (:start_date is NULL or targcompdate between :start_date and :end_date)