[求助]循环计算 - 专家坐堂 - Foxtable(狐表) - 新一代数据库软件，完美融合Access、Foxpro、Excel、vb.net之优势，人人都能掌握的快速软件开发工具!

针对表C中每一行的第五列和第六列都进行距离运算：

Dim x1 As Double = 1
Dim y1 As Double = 1
Dim x2 As Double = 2
Dim y2 As Double = 2

Dim rad As Double = 6371
Dim p1X As Double = X1 / 180 * Math.PI
Dim p1Y As Double = Y2 / 180 * Math.PI
Dim p2X As Double = X2 / 180 * Math.PI
Dim p2Y As Double = Y2 / 180 * Math.PI
Dim result As Double = Math.Acos(Math.Sin(p1Y) * Math.Sin(p2Y) + Math.Cos(p1Y) * Math.Cos(p2Y) * Math.Cos(p2X - p1X)) * rad
msgbox(result)

最后得出的数值赋值到表C的每一行第七列怎么计算呢

对，已经换算成小数点形式了

哦，对，

For Each n As String In DataTables("表A").GetValues("第一列", "第一列 is not null")

Dim dr1 As DataRow = DataTables("表A").Find("第一列 = '" & n & "'", "第二列")

Dim dr2 As DataRow = DataTables("表A").Find("第一列 = '" & n & "'", "第二列 desc")

Dim fdr As DataRow = DataTables("表D").Find("第一列 = '" & n & "'")

If fdr Is Nothing Then

fdr = DataTables("表D").AddNew

fdr("第一列") = n

End If

fdr("第二列“) = math.Abs(dr2("第五列") - dr1("第五列"))

fdr("第三列") = math.Abs(dr2("第六列") - dr1("第六列"))

就比如这个函数，假设筛选出来的一对数值不再做减法运算，而筛选出是他们的经纬度，从而计算出最早与最晚的距离。然后赋值到表D中

Cannot set column '第一列'. The value violates the MaxLength limit of this column.

这个是什么问题呢？

255还不够吗？设置成多少

以下是引用有点甜在2014-6-17 9:59:00的发言：

取决于你字符的长度。你的是外部数据表吗？是不是设置了约束？

我把代码输入进去，结果导入内部数据源的时候，名称都变了，所以我就把代码第一列都替换为GPS产品名称了，然后经纬度都替换第五列，第六列了（其余也都替换成功，变色了！，可是代码第一列后半部分换成GPS产品名称后却变灰了。显示cant find colume [GPS产品名称]

以下是引用有点甜在2014-6-17 15:27:00的发言：

呃，不明白你的意思，红色代码如果不需要，可以删掉。请上传具体的例子说明你的问题。

For Each n As String In DataTables("表A").GetValues("第一列", "第一列 is not null")
    Dim dr1 As DataRow = DataTables("表A").Find("第一列 = '" & n & "'", "第二列")
    Dim dr2 As DataRow = DataTables("表A").Find("第一列 = '" & n & "'", "第二列 desc")
    Dim fdr As DataRow = DataTables("表D").Find("第一列 = '" & n & "'")
    If fdr Is Nothing Then
        fdr = DataTables("表D").AddNew
        fdr("第一列") = n
    End If
    Dim x1 As Double = dr1("第五列")
    Dim y1 As Double = dr1("第六列")
    Dim x2 As Double = dr2("第五列")
    Dim y2 As Double = dr2("第六列")

    Dim rad As Double = 6371
    Dim p1X As Double = X1 / 180 * Math.PI
    Dim p1Y As Double = Y2 / 180 * Math.PI
    Dim p2X As Double = X2 / 180 * Math.PI
    Dim p2Y As Double = Y2 / 180 * Math.PI
    Dim result As Double = Math.Acos(Math.Sin(p1Y) * Math.Sin(p2Y) + Math.Cos(p1Y) * Math.Cos(p2Y) * Math.Cos(p2X - p1X)) * rad
    fdr("第二列") = result
Next

下载信息 [文件大小：下载次数： ]
点击浏览该文件:管理项目4.table

代码是这样的

For Each n As String In DataTables("产品").GetValues("产品", "产品 is not null")
    Dim dr1 As DataRow = DataTables("产品").Find("产品 = '" & n & "'", "日期")
    Dim dr2 As DataRow = DataTables("产品").Find("产品 = '" & n & "'", "日期 desc")
    Dim fdr As DataRow = DataTables("表C").Find("产品 = '" & n & "'")
    If fdr Is Nothing Then
        fdr = DataTables("表C").AddNew
        fdr("产品") = n
    End If
    Dim x1 As Double = dr1("经度")
    Dim y1 As Double = dr1("纬度")
    Dim x2 As Double = dr2("经度")
    Dim y2 As Double = dr2("纬度")

    Dim rad As Double = 6371
    Dim p1X As Double = X1 / 180 * Math.PI
    Dim p1Y As Double = Y2 / 180 * Math.PI
    Dim p2X As Double = X2 / 180 * Math.PI
    Dim p2Y As Double = Y2 / 180 * Math.PI
    Dim result As Double = Math.Acos(Math.Sin(p1Y) * Math.Sin(p2Y) + Math.Cos(p1Y) * Math.Cos(p2Y) * Math.Cos(p2X - p1X)) * rad
    fdr("日期") = result
Next

麻烦帮忙看下为什么执行不了呢？

以下是引用有点甜在2014-6-17 15:43:00的发言：

如下代码

For Each n As String In DataTables("产品").GetValues("GPS产品名称", "GPS产品名称 is not null")
    Dim dr1 As DataRow = DataTables("产品").Find("GPS产品名称 = '" & n & "'", "日期")
    Dim dr2 As DataRow = DataTables("产品").Find("GPS产品名称 = '" & n & "'", "日期 desc")
    Dim fdr As DataRow = DataTables("表C").Find("第一列 = '" & n & "'")
    If fdr Is Nothing Then
        fdr = DataTables("表C").AddNew
        fdr("第一列") = n
    End If
    Dim x1 As Double = dr1("经度")
    Dim y1 As Double = dr1("纬度")
    Dim x2 As Double = dr2("经度")
    Dim y2 As Double = dr2("纬度")

    Dim rad As Double = 6371
    Dim p1X As Double = X1 / 180 * Math.PI
    Dim p1Y As Double = Y2 / 180 * Math.PI
    Dim p2X As Double = X2 / 180 * Math.PI
    Dim p2Y As Double = Y2 / 180 * Math.PI
    Dim result As Double = Math.Acos(Math.Sin(p1Y) * Math.Sin(p2Y) + Math.Cos(p1Y) * Math.Cos(p2Y) * Math.Cos(p2X - p1X)) * rad
    fdr("第二列") = result
Next

搞定！！感谢！！

以后这个第一列和第二列必须都得是固定的格式了是把！就是第一列必须是GPS产品名称，第二列必须是开始时间是吧？？

谢谢有点甜老师。顶一个。正在看你的视频！讲的真好对新手很有用！

我现在针对的数据都是他们报给我的EXCEL表格，但是是CSV格式的，有的统计数据特别多，1000多万条，固定的格式，我想问有点甜老师，我就针对你的视频从头学习就可以吗？CSV格式可以导入里面吗？或者转成别的格式呢？

有点甜老师，我把帮主文件都看了一遍，所以我想学习针对ACESS导入和针对数据计算和操作等代码信息！包括做一个界面等，我应该怎么入手呢？学习些什么视频呢

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