请帮助解释一下：这是下载的范例中的模块

yanwei82123300

Public Function k(strCodeID As String, lngY As Long, lngM As Long) As Long
    Dim strSQL As String
    Dim rs As Object
    Dim cn As Object
   
    Set cn = Application.CurrentProject.Connection
    Set rs = CreateObject("ADODB.Recordset")
   
    '
    strSQL = "SELECT 材料收支表.材料ID, Sum(([进库]-[出库])) AS 库存 " & _
             "FROM 材料收支表 " & _
             "WHERE 材料收支表.日期 < #" & lngM & "/1" & "/" & lngY & "# And 材料ID ='" & strCodeID & "' " & _
             "GROUP BY 材料收支表.材料ID;"
    rs.Open strSQL, cn, 1
   
    If rs.EOF = True Then Exit Function
   
    k = rs("库存")
    'MsgBox k
   
    rs.Close
    Set rs = Nothing
    Set cn = Nothing
End Function

aslxt

这是一个从【材料收支表】表中查询指定材料（strCodeID）、指定年（lngY）月（lngM）的期初库存的函数

yanwei82123300

Thank you aslxt