参考代码

Dim d1 As Date = "2018-9-11"
Dim d2 As Date = "2011-10-10"
Dim y,m,d As Integer
DateYMD(d2, d1, y, m, d)
msgbox(y & " " & m & " " & d)
If d <> 0 Then
    m += 1
    d = 0
End If
If m = 12 Then
    y += 1
    m = 0
End If
msgbox(y & " " & m)

目前参照论坛实例编写如下代码能够计算到年月日。至于见日进月，能在下面的代码基础上进行修改么？

If e.DataCol.Name = "工作年月" OrElse e.DataCol.Name = "退休月份" Then
    Dim dr As DataRow = e.DataRow
    If dr.IsNull("工作年月") OrElse dr.IsNull("退休月份") OrElse dr("工作年月")> dr("退休月份") Then
        dr("连续工龄") = Nothing
    Else
        Dim d1,d2 As Date
        Dim y,m,d As Integer
        d1= dr("工作年月")
        d2=dr("退休月份").Adddays(1)
        y=DateDiff("yyyy",d1,d2)
        m=DateDiff("m",d1,d2)
        d=DateDiff("d",d1,d2)
       
        y = y +val(d1.AddYears(y)>d2)
        m = m+val(d1.AddMonths(m)>d2)-12*y
        d= d-DateDiff("d",d1,d1.addmonths(y*12+m))
        dr("连续工龄") =  iif(y = 0, "",y & "年") & iif(m = 0,"",m & "个月") & iif(d = 0,"",d & "日")
    End If
End If