代码

Dim dtb As DataTable = DataTables("表B")
Dim dta As DataTable = DataTables("表A")
dtb.DataRows.Clear

Dim filter As String = "1=1"
Dim filter2 As String = "1=1"

Dim c1 As WinForm.ComboBox = e.Form.Controls("ComboBox1")
Dim c2 As WinForm.ComboBox = e.Form.Controls("ComboBox2")

If c1.Text > "" Then
    filter &= " and Convert(月份, \'System.Int32\') >= " & c1.text
End If

If c2.Text > "" Then
    filter &= " and Convert(月份, \'System.Int32\') <= " & c2.text
    filter2 &= " and Convert(月份, \'System.Int32\') <= " & c2.text
End If

For Each name As String In dta.GetValues("姓名", "姓名 is not null")
    Dim ndr As DataRow = dtb.AddNew
    ndr("姓名") = name
    ndr("本期工资") = dta.Compute("sum(月工资)", filter & " and 姓名 = \'" & name & "\'")
    ndr("全年累计") = dta.Compute("sum(月工资)", filter2 & " and 姓名 = \'" & name & "\'")
Next