首先，我们需要一个mysql连接，并且需要创建一个datagridview，用于显示表中的数据。如果表中最初不包含所需的所有列，则需要手动向表添加它们。

使用以下代码创建mysql连接：

Dim connStr As String = "server=localhost;user=root;password=yourPassword;database=yourDatabase"
Dim conn As New MySqlConnection(connStr)

Try
    conn.Open()
Catch ex As Exception
    '处理连接错误
End Try

接下来，我们需要填充datagridview，以便从表中读取数据。使用以下代码执行此操作：

Dim query As String = "SELECT * FROM yourTableName"
Dim cmd As New MySqlCommand(query, conn)
Dim adapter As New MySqlDataAdapter(cmd)
Dim table As New DataTable()
adapter.Fill(table)

DataGridView1.DataSource = table

现在，我们可以更新mysql表中的数据并从datagridview计算新值。使用以下代码更新表中的所有行：

For Each row As DataGridViewRow In DataGridView1.Rows
    Dim id As Integer = CInt(row.Cells("id_columnName").Value)
    Dim newValue As Double '计算新值

    '执行计算
    newValue = ...

    Dim query As String = "UPDATE yourTableName SET yourColumnName=" & newValue & " WHERE id=" & id
    Dim cmd As New MySqlCommand(query, conn)
    cmd.ExecuteNonQuery()
Next

请注意，您需要将“id_columnName”替换为包含表中id值的列的名称，将“yourColumnName”替换为要更新的计算列的名称。

一个完成的示例可以看起来像这样：

Dim connStr As String = "server=localhost;user=root;password=yourPassword;database=yourDatabase"
Dim conn As New MySqlConnection(connStr)

Try
    conn.Open()
Catch ex As Exception
    '处理连接错误
End Try

Dim query As String = "SELECT * FROM yourTableName"
Dim cmd As New MySqlCommand(query, conn)
Dim adapter As New MySqlDataAdapter(cmd)
Dim table As New DataTable()
adapter.Fill(table)

DataGridView1.DataSource = table

For Each row As DataGridViewRow In DataGridView1.Rows
    Dim id As Integer = CInt(row.Cells("id_columnName").Value)
    Dim newValue As Double '计算新值

    '执行计算
    newValue = ...

    Dim query As String = "UPDATE yourTableName SET yourColumnName=" & newValue & " WHERE id=" & id
    Dim cmd As New MySqlCommand(query, conn)
    cmd.ExecuteNonQuery()
Next

conn.Close()

请注意，这只是一个示例代码，您需要