Sql 访问查询中的If/Then

我需要一些在Access中构造If/Then查询的帮助。我希望根据持卡人、审批人和对账人列填充新的注释字段：

If only Cardholder is filled: New Comments field = A
If only Reconciler is filled: New Comments field = B
If only Approver is filled: New Comments field = C
If Cardholder & Reconciler filled:  New Comments field =D
If Cardholder & Approver filled: New Comments field = E
If Cardholder & Reconciler & Approver filled: New Comments field = F
If Reconciler & Approver filled: New Comments field = G

---

您能帮忙吗？

因为您有三个字段，每个字段可以是

Null

或

notnull

有23=8种可能的情况

以下将说明每种情况：

NewComments: 
IIf([Cardholder] Is Not Null And [Reconciler] Is Not Null And [Approver] Is Not Null,"F",
    IIf([Cardholder] Is Not Null And [Reconciler] Is Not Null,"D",
        IIf([Cardholder] Is Not Null And [Approver] Is Not Null,"E",
            IIf([Reconciler] Is Not Null And [Approver] Is Not Null,"G",
                IIf([Cardholder] Is Not Null,"A",
                    IIf([Reconciler] Is Not Null,"B",
                        IIf([Approver] Is Not Null,"C",
                            "H"
                        )
                    )
                )
            )
        )
    )
)

最终结果

“H”

对应于所有三个字段都为

Null

的情况

---

显然，可以反转逻辑，从每个语句中删除

Not

，但我已经根据您提供的示例构造了该语句。

因为您有三个字段，每个字段可以是

Null

或

notnull

，有23=8种可能的情况

以下将说明每种情况：

NewComments: 
IIf([Cardholder] Is Not Null And [Reconciler] Is Not Null And [Approver] Is Not Null,"F",
    IIf([Cardholder] Is Not Null And [Reconciler] Is Not Null,"D",
        IIf([Cardholder] Is Not Null And [Approver] Is Not Null,"E",
            IIf([Reconciler] Is Not Null And [Approver] Is Not Null,"G",
                IIf([Cardholder] Is Not Null,"A",
                    IIf([Reconciler] Is Not Null,"B",
                        IIf([Approver] Is Not Null,"C",
                            "H"
                        )
                    )
                )
            )
        )
    )
)

最终结果

“H”

对应于所有三个字段都为

Null

的情况

---

显然，可以颠倒逻辑，从每个语句中删除

而不是
，但我已根据您提供的示例构造了该语句。
在MS Access中，
开关是处理多个条件的更简单方法：

select . . .
       switch([Cardholder] Is Not Null And [Reconciler] Is Not Null And [Approver] Is Not Null, "F",
              [Cardholder] Is Not Null And [Reconciler] Is Not Null, "D",
              [Cardholder] Is Not Null And [Approver] Is Not Null, "E",
              [Reconciler] Is Not Null And [Approver] Is Not Null, "G",
              [Cardholder] Is Not Null, "A",
              [Reconciler] Is Not Null, "B",
              [Approver] Is Not Null, "C",
              1=1, "H"
             )

在MS Access中，
开关
是处理多种情况的更简单方法：

select . . .
       switch([Cardholder] Is Not Null And [Reconciler] Is Not Null And [Approver] Is Not Null, "F",
              [Cardholder] Is Not Null And [Reconciler] Is Not Null, "D",
              [Cardholder] Is Not Null And [Approver] Is Not Null, "E",
              [Reconciler] Is Not Null And [Approver] Is Not Null, "G",
              [Cardholder] Is Not Null, "A",
              [Reconciler] Is Not Null, "B",
              [Approver] Is Not Null, "C",
              1=1, "H"
             )

您可以忽略上面列出的代码格式--这些只是我希望用于If/Then查询的参数您可以忽略上面列出的代码格式--这些只是我希望用于If/Then查询的参数