MS Access查询：在Switch（）函数中使用select语句

Question

我正在使用switch（）函数获取MS Access查询中的条件更新。下面是我的查询

UPDATE T_Generated_OpportunityLine SET PlContact_c = Switch(
LowestlevelValue_c='PTFDS - FD ENCLOSURE SYSTEMS',Select OpportunityLine_PostCode.SESA from OpportunityLine_PostCode,T_Generated_OpportunityLine where OpportunityLine_PostCode.Postcode=T_Generated_OpportunityLine.Selected_Zip AND 
OpportunityLine_PostCode.OpptyLine_Ref='PTFDS', 
LowestlevelValue_c='DOOR ENTRY SYSTEM',Select OpportunityLine_PostCode.SESA from OpportunityLine_PostCode,T_Generated_OpportunityLine where OpportunityLine_PostCode.Postcode=T_Generated_OpportunityLine.Selected_Zip AND 
OpportunityLine_PostCode.OpptyLine_Ref='Door Entry System' 
); 

我知道带开关的语法（）函数：

Switch (expression1, value1, expression2, value2, ... expression_n, value_n) 

我刚才提出的，而不是通过静态值“值”一种修饰，即部分我通过选择查询动态获取此值。

但是，当我试图执行其声称的错误信息查询：

The query must be an updatable query 

我相信这个问题是选择语句内切换（）函数，但我需要户口本上有条件更新我的项目。

任何人都可以提供任何合适的解决方案吗？我也想知道我们可以在Switch（）语法中传递“Value”部分的动态值吗？

Answer 1

我不知道这是不是你的问题，但通常的子查询必须用括号括起来：

UPDATE T_Generated_OpportunityLine 
    SET PlContact_c = Switch(LowestlevelValue_c='PTFDS - FD ENCLOSURE SYSTEMS', 
           (Select SESA 
           from OpportunityLine_PostCode 
           where OpportunityLine_PostCode.Postcode = T_Generated_OpportunityLine.Selected_Zip AND 
             OpportunityLine_PostCode.OpptyLine_Ref = 'PTFDS' 
          ), 
           LowestlevelValue_c = 'DOOR ENTRY SYSTEM', 
           (Select SESA 
           from OpportunityLine_PostCode 
           where OpportunityLine_PostCode.Postcode = T_Generated_OpportunityLine.Selected_Zip AND 
            OpportunityLine_PostCode.OpptyLine_Ref='Door Entry System' 
          )); 

不过，我只用一个子查询写：

UPDATE T_Generated_OpportunityLine 
    SET PlContact_c = (Select SESA 
         from OpportunityLine_PostCode as pc 
         where pc.Postcode = T_Generated_OpportunityLine.Selected_Zip AND 
           (T_Generated_OpportunityLine.LowestlevelValue_c = 'PTFDS - FD ENCLOSURE SYSTEMS' AND pc.OpptyLine_Ref = 'PTFDS' OR 
           T_Generated_OpportunityLine.LowestlevelValue_c = 'DOOR ENTRY SYSTEM' AND op.OpptyLine_Ref='Door Entry System' 
          ) 
         );