如何修改Microsoft Access查询代码以支持单条件搜索留空另一项

SELECT C1.ConsultID, C1.Consult_No, C1.Consult_Type, C1.Intake_Date, C1.Adult_Peds, C1.Title, C1.ConsultSummary
FROM ([Intersection Query Pre-Reasons] AS C1 LEFT JOIN tblConsultReasons AS C2 ON C1.ConsultID = C2.ConsultID) LEFT JOIN tblConsultReasons AS C3 ON C2.ConsultID = C3.ConsultID
WHERE 
(
    (C2.Reason = Forms!FrmReasonsCriteria!Reason1 AND C2.ReasonType = "Discerned") 
    OR Len(Forms!FrmReasonsCriteria!Reason1 & "") = 0
)
AND 
(
    (C3.Reason = Forms!FrmReasonsCriteria!Reason2 AND C3.ReasonType = "Discerned") 
    OR Len(Forms!FrmReasonsCriteria!Reason2 & "") = 0
);

• 针对每个原因输入框，添加了空值判断逻辑：Len(Forms!FrmReasonsCriteria!ReasonX & "") = 0，这个判断会同时覆盖输入框为Null或空字符串的情况。
• 当某个输入框留空时，对应的条件会自动成立，不需要强制匹配原因；只有当输入框有内容时，才会要求对应的Reason和ReasonType匹配。
• 保留了原查询的核心逻辑：当两个原因都输入时，仍然返回同时满足两个Discerned原因的记录。

内容的提问来源于stack exchange，提问作者jim